Relative Clauses

A relative clause is a dependent clause that modifies a noun. It begins with a relative pronoun -- who, whom, whose, which, that -- or a relative adverb -- where, when, why. Relative clauses let you add essential or extra information about a noun without writing a separate sentence.

Mastering relative clauses is critical for writing at an advanced level. They allow you to embed detail directly into your sentences, making your writing more precise, more varied, and more cohesive.

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Relative Pronouns and Relative Adverbs

Word	Refers to	Example
who	people (subject)	The researcher who conducted the study presented the findings.
whom	people (object)	The candidate whom the committee selected starts on Monday.
whose	possession (people or things)	The author whose book won the prize gave a lecture.
which	things, animals, ideas	The report, which was published last week, contains new data.
that	people or things (defining clauses only)	The policy that the board approved takes effect in January.
where	places	The office where I work is being renovated.
when	times	I remember the day when the results were announced.
why	reasons (after "the reason")	That is the reason why she declined the offer.

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Defining vs. Non-Defining Relative Clauses

This is the most important distinction in relative clause grammar. It affects meaning, punctuation, and which pronouns you can use.

Defining (Restrictive) Relative Clauses

A defining relative clause identifies or restricts the noun it modifies. It tells the reader which one you mean. Without it, the sentence loses essential meaning or becomes vague.

The students who submitted their essays on time received full marks.

Which students? Only those who submitted on time. The relative clause defines the group.

The laptop that I bought last month has already stopped working.

Which laptop? The one bought last month.

Rules for defining clauses:

1. No commas. The clause is tightly bound to the noun.
2. "That" is allowed (and often preferred in informal writing).
3. The relative pronoun can be omitted when it functions as the object of the clause.

The book (that) I recommended is out of print.

Here, that is the object of recommended (I recommended the book). Because it is an object, you can drop it. This is called a contact clause or zero relative pronoun.

The person (whom/that) you spoke to is the manager.

Again, the pronoun is the object of spoke to, so it can be omitted.

You cannot omit the pronoun when it is the subject:

The person who called you is waiting outside.

The person called you is waiting outside. (Incorrect -- who is the subject of called.)

Non-Defining (Non-Restrictive) Relative Clauses

A non-defining relative clause adds extra information about a noun that is already clearly identified. The information is supplementary -- useful, but not essential for identifying the noun.

Professor Garcia, who has taught here for twenty years, is retiring next month.

We already know which person we mean (Professor Garcia). The relative clause adds a detail.

The annual report, which was released yesterday, shows a 12% increase in revenue.

The annual report is already specific. The clause provides additional context.

Rules for non-defining clauses:

1. Commas are required -- one before and one after the clause (or one before if the clause ends the sentence).
2. "That" is NOT allowed. Use who for people and which for things.
3. The relative pronoun cannot be omitted.

Feature	Defining	Non-Defining
Commas	No	Yes
"That" allowed	Yes	No
Pronoun omission	Yes (when object)	No
Meaning if removed	Sentence changes meaning	Sentence still makes sense
Purpose	Identifies which one	Adds extra info

How Commas Change Meaning

The presence or absence of commas can completely change what a sentence means:

The employees who work remotely receive a technology stipend.

Defining: Only those employees who work remotely receive the stipend. Others do not.

The employees, who work remotely, receive a technology stipend.

Non-defining: All the employees (who happen to work remotely) receive the stipend.

This difference is subtle but significant. Always ask yourself: "Am I identifying which noun I mean, or am I adding extra information about an already-identified noun?"

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"Whose" for Possession

Whose shows that something belongs to the noun being modified. It works for both people and things.

The student whose research was cited presented at the conference.

The company whose profits declined laid off 200 workers.

I spoke to a woman whose daughter studies medicine.

Common error: Confusing whose with who's (which means "who is" or "who has").

Incorrect	Correct
The writer who's book was published...	The writer whose book was published...

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"Which" Referring to a Whole Clause

In non-defining clauses, which can refer to an entire preceding statement, not just a single noun:

The team finished the project ahead of schedule, which impressed the client.

Here, which refers to the fact that the team finished early -- the whole previous clause.

He refused to apologize, which made the situation worse.

This usage is always non-defining and always requires a comma.

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Reducing Relative Clauses

In many cases, relative clauses can be shortened (reduced) to make sentences more concise. This is especially useful in formal and academic writing.

Reducing with a Present Participle (-ing)

When the relative pronoun is the subject and the verb is in the active voice, you can replace the pronoun + verb with a present participle:

Full: The students who are studying abroad will return in June.

Reduced: The students studying abroad will return in June.

Full: Anyone who wishes to participate should register online.

Reduced: Anyone wishing to participate should register online.

Reducing with a Past Participle (-ed / -en)

When the relative pronoun is the subject and the verb is in the passive voice, you can replace the pronoun + be-verb with a past participle:

Full: The report that was submitted yesterday contained errors.

Reduced: The report submitted yesterday contained errors.

Full: The equipment which was damaged in the storm has been replaced.

Reduced: The equipment damaged in the storm has been replaced.

Reducing with an Adjective or Prepositional Phrase

When the relative clause contains be + adjective or be + prepositional phrase, you can omit the pronoun + be:

Full: The options that are available to you are listed below.

Reduced: The options available to you are listed below.

Full: The files which are on the desktop need to be archived.

Reduced: The files on the desktop need to be archived.

When NOT to Reduce

• Do not reduce if the meaning becomes ambiguous.
• Non-defining clauses with which referring to a whole clause cannot be reduced.
• Clauses with modal verbs (who can, which might) usually cannot be reduced.

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Common Mistakes with Relative Clauses

1. Using "That" in Non-Defining Clauses

Incorrect	Correct
My sister, that lives in London, is visiting.	My sister, who lives in London, is visiting.
The proposal, that was rejected, has been revised.	The proposal, which was rejected, has been revised.

2. Missing Commas in Non-Defining Clauses

Incorrect	Correct
Dr. Tanaka who joined last year leads the lab.	Dr. Tanaka, who joined last year, leads the lab.

3. Adding Unnecessary Pronouns

Incorrect	Correct
The book which I read it was interesting.	The book which I read was interesting.
The person who she helped me was kind.	The person who helped me was kind.

The relative pronoun already replaces the noun inside the clause. Do not add another pronoun for the same role.

4. Using "Who" for Things or "Which" for People

Incorrect	Correct
The car who I rented broke down.	The car that/which I rented broke down.
The teacher which helped me was very patient.	The teacher who helped me was very patient.

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Practice Tip

Take two related simple sentences and combine them using a relative clause. Then decide: is the clause defining or non-defining? Add or remove commas accordingly. Finally, try reducing the clause. Can you make it shorter without losing clarity? This three-step exercise (combine, classify, reduce) builds all the key relative clause skills at once.

Noun Clauses and Adverbial Clauses

Beyond subordinating conjunctions and relative clauses, two other types of dependent clauses appear frequently in complex sentences: noun clauses and adverbial clauses. Each plays a different grammatical role in the sentence, and understanding both gives you the full toolkit for constructing sophisticated, varied prose.

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Part 1: Noun Clauses

A noun clause is a dependent clause that functions as a noun. Just as a single noun can serve as a subject, object, or complement, so can an entire clause.

How to Recognize a Noun Clause

Noun clauses typically begin with one of these words:

Starter Word	Example
that	I believe that the results are accurate.
what	What she said surprised everyone.
whatever	You can order whatever you like.
who / whoever	Whoever finishes first may leave.
whom / whomever	Give the award to whomever the committee selects.
which / whichever	Choose whichever option works best.
where	I don't know where the meeting is.
when	She asked when the deadline was.
why	He explained why the project was delayed.
how	The manual describes how the software works.
whether / whether or not	I wonder whether the proposal will be accepted.
if (informal for whether)	She asked if we could reschedule.

The test is simple: if you can replace the clause with the word "something" or "someone" and the sentence still makes grammatical sense, you have a noun clause.

That the project failed surprised no one. --> Something surprised no one. (Works -- it is a noun clause functioning as the subject.)

Noun Clauses as Subjects

A noun clause can serve as the subject of a sentence. This structure is common in formal and academic writing.

What the data reveals is a clear trend toward remote work.

Whether the vaccine is effective remains an open question.

That she was promoted so quickly surprised her colleagues.

How the brain processes language is still not fully understood.

Note that when a that-clause is the subject, you cannot omit that:

Incorrect	Correct
She was promoted so quickly surprised her colleagues.	That she was promoted so quickly surprised her colleagues.

"It" as a placeholder subject: Because subject noun clauses can be long, English often moves them to the end of the sentence and uses it as a placeholder:

It is clear that the experiment needs to be repeated. (Instead of: That the experiment needs to be repeated is clear.)

It remains uncertain whether the funding will continue. (Instead of: Whether the funding will continue remains uncertain.)

Both structures are correct, but the it version is more common in everyday writing because it puts the main verb closer to the beginning of the sentence.

Noun Clauses as Objects

This is the most common position for noun clauses. They appear after verbs like know, believe, think, say, suggest, wonder, decide, discover, realize, and explain.

The researchers discovered that the compound was toxic at high doses.

I don't know where she went.

Can you explain how this formula works?

The committee will decide whether to approve the budget.

She wondered why the results were inconsistent.

Omitting "that" in object clauses: When a that-clause is the object (not the subject), that can often be omitted in informal and neutral writing:

I think (that) the deadline is too tight.

She said (that) she would attend.

We believe (that) the approach is sound.

In formal or academic writing, keeping that is recommended because it improves clarity, especially in longer sentences.

Noun Clauses as Complements

A noun clause can follow a linking verb (be, seem, appear) to complete the meaning of the subject:

The problem is that we lack sufficient data.

The question remains whether we should proceed.

The truth is that no single solution exists.

Noun Clauses After Prepositions

Some prepositions can be followed by noun clauses, though this is less common:

The decision depends on what the board recommends.

I am concerned about whether the deadline is realistic.

Note: that-clauses generally do not follow prepositions directly. Use the fact that as a bridge:

I am aware of that she resigned.

I am aware of the fact that she resigned.

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Part 2: Adverbial Clauses

An adverbial clause is a dependent clause that functions as an adverb -- it modifies a verb, adjective, or another adverb by answering questions like when?, where?, why?, how?, under what conditions?, or to what extent?

Adverbial clauses begin with subordinating conjunctions (covered in Section 1). What distinguishes them from noun clauses is their grammatical role: they modify rather than act as subjects or objects.

Types of Adverbial Clauses

1. Adverbial Clauses of Time

These answer the question when? and use conjunctions like when, whenever, before, after, until, while, as, as soon as, once, since, by the time.

Before the meeting starts, please review the agenda.

The system will remain offline until the maintenance is complete.

Whenever demand spikes, the supply chain struggles to keep up.

As soon as the results were published, the media reported on them.

2. Adverbial Clauses of Place

These answer the question where? and use conjunctions like where, wherever, everywhere.

Where the river bends, the current is strongest.

You can sit wherever you like.

Everywhere they looked, they found evidence of contamination.

3. Adverbial Clauses of Reason

These answer the question why? and use conjunctions like because, since, as, now that, given that.

Because the sample size was small, the results should be interpreted cautiously.

The flight was delayed since visibility was poor.

Given that resources are limited, we must prioritize.

4. Adverbial Clauses of Condition

These answer the question under what conditions? and use conjunctions like if, unless, provided that, as long as, even if, in case, whether or not.

If the temperature exceeds 40 degrees, the equipment will shut down automatically.

The event will proceed unless severe weather is forecast.

You may use the data provided that you cite the source.

5. Adverbial Clauses of Concession

These express a contrast or unexpected result. They use conjunctions like although, though, even though, whereas, while, even if.

Although the study had limitations, its conclusions were widely accepted.

The product sold well, even though reviews were mixed.

Whereas the first trial failed, the second one produced significant results.

6. Adverbial Clauses of Purpose

These answer the question for what purpose? and use conjunctions like so that, in order that.

She spoke slowly so that everyone could follow.

The data was encrypted in order that unauthorized users could not access it.

7. Adverbial Clauses of Result

These express the consequence of an action or condition. They use so...that and such...that.

The noise was so loud that we could not hear each other.

It was such a complex problem that no one could solve it immediately.

8. Adverbial Clauses of Manner

These answer the question how? and use conjunctions like as, as if, as though.

She completed the task as the instructor had demonstrated.

He spoke as if he had rehearsed every word.

The building looked as though it had been abandoned for years.

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Noun Clauses vs. Adverbial Clauses: How to Tell Them Apart

The key difference is the grammatical role the clause plays:

Feature	Noun Clause	Adverbial Clause
Function	Acts as a noun (subject, object, complement)	Acts as an adverb (modifies verb/adjective)
Can be replaced by	A noun or pronoun ("something," "it")	An adverb or adverb phrase ("then," "for that reason")
Typical starters	that, what, whether, how, who, where, when, why, if	because, although, when, if, while, since, unless, so that
Removable?	No -- the sentence would lose its subject or object	Often yes -- the sentence still makes sense without it

Test sentences:

When the project is finished -- Can you replace this with "something"? Something surprised me. No, it does not fit as a noun in context. It answers "when?" --> Adverbial clause.

I don't know when the project will be finished -- Can you replace this with "something"? I don't know something. Yes! --> Noun clause.

The same word (when) introduces different clause types depending on its function. This is why understanding the role of the clause matters more than memorizing the starter word.

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Common Mistakes

1. Confusing "If" and "Whether" in Noun Clauses

In formal writing, use whether (not if) when the clause is a subject or follows a preposition:

Less formal / ambiguous	Formal / clear
If we should continue is unclear.	Whether we should continue is unclear.
It depends on if they accept.	It depends on whether they accept.

As an object after verbs like know, wonder, decide, both if and whether are acceptable:

I wonder if/whether the store is open.

2. Incorrect Word Order in Noun Clauses

Noun clauses use statement word order (subject before verb), not question word order:

Incorrect (question order)	Correct (statement order)
I don't know where is the library.	I don't know where the library is.
Can you tell me what time does the train leave?	Can you tell me what time the train leaves?
She asked why was the flight delayed.	She asked why the flight was delayed.

This is one of the most frequent errors in complex sentence writing. Remember: once a question becomes a noun clause inside a statement, it loses its question word order.

3. Missing the Main Clause in Adverbial Clauses

Just as with subordinating conjunctions, an adverbial clause cannot stand alone:

Fragment	Complete
Although the instructions were clear.	Although the instructions were clear, some participants made errors.
Because we ran out of time.	Because we ran out of time, we postponed the final discussion.

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Practice Tip

Write five sentences using noun clauses (try each position: subject, object, complement) and five using adverbial clauses (try different types: time, reason, condition, concession). For each sentence, identify the clause and label its type. Then try substituting the noun clause with "something" and the adverbial clause with a single adverb to confirm you have classified them correctly.

Punctuating Complex Sentences

Punctuation in complex sentences follows clear, consistent rules. Once you learn the patterns, you can punctuate any complex sentence with confidence. This section covers every major punctuation scenario you will encounter, with detailed examples and a focus on the errors writers make most often.

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The Core Rule: Clause Order Determines Punctuation

The fundamental punctuation rule for complex sentences depends on which clause comes first.

Pattern 1: Dependent Clause First --> Comma

When the dependent clause opens the sentence, place a comma at the boundary between the dependent and independent clauses.

Because the survey response rate was low, the researchers extended the deadline.

Although the initial results were promising, further testing revealed several flaws.

If you plan to attend the conference, please register by March 15.

When the semester ends, the library will reduce its hours.

While the committee deliberated, staff members prepared the final report.

The comma serves as a signal to the reader: "The introductory information is finished. The main point starts here." Without it, readers may stumble because they cannot immediately see where the dependent clause ends and the independent clause begins.

Pattern 2: Independent Clause First --> No Comma (Usually)

When the independent clause comes first and the dependent clause follows, no comma is needed in most cases.

The researchers extended the deadline because the survey response rate was low.

Further testing revealed several flaws although the initial results were promising.

Please register by March 15 if you plan to attend the conference.

The library will reduce its hours when the semester ends.

The sentence flows naturally from the main idea to the supporting detail, so no pause (comma) is needed.

The Contrast Exception

There is one important exception to Pattern 2. When the dependent clause expresses a contrast or concession using words like although, though, even though, whereas, or while (in its contrast meaning), many writers add a comma even when the independent clause comes first:

The product received strong reviews, although sales remained disappointing.

Enrollment increased by 15%, whereas the budget grew by only 3%.

She accepted the offer, even though the salary was lower than expected.

This comma is not strictly required by all style guides, but it is widely used because it helps the reader anticipate the shift in direction. Think of it as a courtesy pause: "What follows contrasts with what you just read."

When not to add the contrast comma: If the sentence is short and the shift is obvious, you may omit it:

He agreed although he had doubts.

Both versions (with and without the comma) are acceptable. Use the comma when the sentence is long or when clarity benefits from the pause.

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Punctuating Relative Clauses: Restrictive vs. Non-Restrictive

Relative clauses have their own punctuation logic based on whether the clause is defining (restrictive) or non-defining (non-restrictive).

Defining (Restrictive) -- No Commas

A defining relative clause is essential to the meaning of the sentence. It identifies which noun you mean. Because it is tightly bound to the noun, it receives no commas.

The candidates who passed the initial screening will be invited to interview.

Removing the clause changes the meaning: "The candidates will be invited to interview" no longer specifies which candidates.

The software that the team developed has been deployed to production.

Students whose applications are incomplete will not be considered.

The city where the conference takes place is known for its architecture.

Non-Defining (Non-Restrictive) -- Commas Required

A non-defining relative clause adds extra, supplementary information about a noun that is already clearly identified. It is set off with commas -- one before the clause and one after it (or one before if the clause ends the sentence).

Dr. Nakamura, who has led the department for a decade, announced her retirement.

We already know who Dr. Nakamura is. The clause adds a detail.

The annual report, which spans over 200 pages, will be published next week.

Tokyo, where the 2021 Olympics were held, is Japan's capital city.

Critical reminder: Never use that in a non-defining clause.

Incorrect	Correct
The proposal, that was submitted late, was rejected.	The proposal, which was submitted late, was rejected.

How Comma Placement Changes Meaning

Study these pairs carefully:

The volunteers who completed all training sessions were given certificates.

Only those volunteers who completed all sessions received certificates. (Defining -- no commas.)

The volunteers, who completed all training sessions, were given certificates.

All the volunteers completed all sessions and all were given certificates. (Non-defining -- commas.)

My brother who lives in Berlin is visiting next week.

I have more than one brother, and I am identifying the one who lives in Berlin. (Defining.)

My brother, who lives in Berlin, is visiting next week.

I have one brother, and he happens to live in Berlin. (Non-defining.)

The commas are not decorative -- they change the factual content of the sentence.

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Punctuating Noun Clauses

Noun clauses generally require no special punctuation. Because they fill a noun slot (subject, object, complement), they integrate directly into the sentence structure.

I believe that the proposal has merit. (No comma before that.)

What the report reveals is deeply concerning. (No comma after the subject clause.)

The question is whether we have enough evidence. (No comma before whether.)

Common error: Adding a comma before a that-clause after a reporting verb.

Incorrect	Correct
She mentioned, that the deadline had changed.	She mentioned that the deadline had changed.
The study showed, that stress affects performance.	The study showed that stress affects performance.

No comma is needed because the that-clause is the direct object of the verb, just as you would not write "She mentioned, the deadline."

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Common Punctuation Errors in Complex Sentences

Error 1: Missing Comma After an Introductory Dependent Clause

This is the most frequent punctuation mistake in complex sentences.

Incorrect	Correct
Although the evidence was strong the jury deliberated for three days.	Although the evidence was strong*,** the jury deliberated for three days.*
When the power went out we lost all unsaved work.	When the power went out*,** we lost all unsaved work.*
Because she arrived late she missed the opening remarks.	Because she arrived late*,** she missed the opening remarks.*

Without the comma, the reader may initially parse the sentence incorrectly, reading across the clause boundary before realizing the main clause has begun.

Error 2: Comma Splice with Complex Sentences

A comma splice occurs when a comma is used to join two independent clauses without a conjunction. This error sometimes happens when a writer intends a complex sentence but forgets the subordinating conjunction.

Comma splice	Fixed with subordination
The data was inconclusive, the team ran more tests.	Because the data was inconclusive, the team ran more tests.
She finished the report, she submitted it immediately.	After she finished the report, she submitted it immediately.

Error 3: Unnecessary Comma Before "Because"

When because introduces a clause after the independent clause, a comma is generally not needed.

Incorrect (usually)	Correct
She left early**,** because she had a meeting.	She left early because she had a meeting.

However, a comma IS needed when omitting it would cause misreading, especially with negative main clauses:

She did not leave*,** because she had a meeting.* (The comma clarifies: the meeting is the reason she stayed.)

Without the comma, the reader might initially parse this as "She did not leave because she had a meeting" (meaning she left for a different reason).

Error 4: Comma Between Subject and Verb in Noun Clauses

When a noun clause is the subject, do not place a comma between the clause and the main verb.

Incorrect	Correct
What the investigation revealed**,** shocked the public.	What the investigation revealed shocked the public.
Whether the plan will succeed**,** is uncertain.	Whether the plan will succeed is uncertain.

This is the same rule that prevents a comma between any subject and its verb: The report, was published.

Error 5: Missing Commas Around Non-Defining Clauses

Incorrect	Correct
The CEO who founded the company in 1998 stepped down. (if the CEO is already identified)	The CEO, who founded the company in 1998, stepped down.
Mars which is the fourth planet has two moons.	Mars, which is the fourth planet, has two moons.

If you intend the clause to add extra (non-essential) information, you must use commas.

Error 6: Adding Commas Around Defining Clauses

Incorrect	Correct
The students, who submitted late, received a penalty. (if you mean only some students)	The students who submitted late received a penalty.

If you intend the clause to identify which students, do not use commas.

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Summary of Punctuation Rules

Sentence Structure	Comma?	Example
Dependent clause + independent clause	Yes	When the bell rang*,** everyone stood up.*
Independent clause + dependent clause	No (usually)	Everyone stood up when the bell rang.
Independent clause + contrast clause	Optional (recommended)	Sales rose*,** although costs also increased.*
Defining relative clause	No	The report that she wrote was excellent.
Non-defining relative clause	Yes	The report, which she wrote last week, was excellent.
Noun clause (any position)	No	I know that she left. / What he said was true.

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Practice Tip

Take a paragraph of your own writing and circle every comma. For each one, identify the rule that justifies it. If you cannot name a rule, the comma may be unnecessary. Then look for places where you have written a dependent clause at the beginning of a sentence without a comma. This two-step audit (justify existing commas, find missing commas) catches most punctuation errors in complex sentences.

Complex Sentence Patterns Reference

This reference section consolidates all the key information from the previous four sections into quick-lookup tables, categorized lists, and pattern summaries. Use it when you are writing or editing and need to check a specific rule without re-reading the full explanations.

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Subordinating Conjunctions: Complete List by Category

Cause / Reason

Conjunction	Notes
because	Most common; direct cause
since	Also used for time ("since 2010")
as	Also used for time; more formal
now that	Cause based on a new situation
given that	Formal; common in academic writing
seeing that	Informal alternative to "since"
inasmuch as	Very formal; rare outside legal/academic writing

Contrast / Concession

Conjunction	Notes
although	Standard contrast; unexpected result
though	Slightly less formal than although; can also appear at the end of a clause ("He tried, though.")
even though	Stronger emphasis on the unexpected
whereas	Direct comparison of two different things
while	Also used for time; use whereas in formal writing to avoid ambiguity
much as	Concessive; formal ("Much as I admire her work, I disagree.")

Time

Conjunction	Notes
when	At the time that
whenever	Every time that
before	Earlier than
after	Later than
until / till	Up to the point that (till is informal)
while	During the same time
as	At the same time (also cause)
as soon as	Immediately after
once	From the moment that
since	From a past point until now (also cause)
by the time	No later than when
the moment (that)	At the exact instant
every time (that)	Same as whenever
as long as	For the entire duration (also condition)

Condition

Conjunction	Notes
if	Basic condition
unless	Except if; means "if...not"
provided (that)	On the condition that; formal
providing (that)	Same as provided that; slightly less formal
as long as	On the condition that (also time)
so long as	Same as as long as
even if	Regardless of whether
in case	As a precaution
whether or not	Regardless of the outcome
on condition that	Formal; used in agreements
supposing (that)	Hypothetical condition
assuming (that)	Taking for granted that

Purpose

Conjunction	Notes
so that	Standard purpose conjunction
in order that	More formal version of so that
lest	Very formal; means "for fear that" ("Speak clearly lest you be misunderstood.")

Result

Pattern	Notes
so + adjective/adverb + that	The noise was so loud that we left.
such + noun phrase + that	It was such a long delay that passengers complained.

Manner

Conjunction	Notes
as	In the way that
as if	Suggests something is not true or is uncertain
as though	Same as as if; slightly more formal

Place

Conjunction	Notes
where	At/in the place that
wherever	In any place that
everywhere	In all places that

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Relative Pronouns and Adverbs: Quick Reference

Word	Refers to	Defining?	Non-Defining?	Can omit?
who	People (subject)	Yes	Yes	No
whom	People (object)	Yes	Yes	Yes (in defining)
whose	Possession (people/things)	Yes	Yes	No
which	Things/ideas	Yes (less common)	Yes	Yes (in defining, when object)
that	People or things	Yes	No	Yes (when object)
where	Places	Yes	Yes	No
when	Times	Yes	Yes	Sometimes
why	Reasons	Yes	Rare	Sometimes

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Noun Clause Starters: Quick Reference

Starter	Example
that	I know that she left.
what / whatever	What you said was helpful.
who / whoever	Whoever arrives first can choose a seat.
whom / whomever	Give it to whomever you trust.
which / whichever	Choose whichever option suits you.
where	I forgot where I parked.
when	She asked when we would arrive.
why	He explained why the plan changed.
how	The guide describes how to apply.
whether (or not)	I wonder whether it will rain.
if	She asked if we could help.

Word order rule: Noun clauses use statement order (subject + verb), not question order.

Question	Noun clause
Where is the library?	I don't know where the library is.
What did she say?	I wonder what she said.
When does the train leave?	Can you tell me when the train leaves?

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Punctuation Rules Summary

Complex Sentences with Subordinating Conjunctions

Pattern	Comma?	Example
DC, IC (dependent first)	Yes	Because it rained, the game was canceled.
IC DC (independent first)	No	The game was canceled because it rained.
IC, DC (contrast clause)	Optional	Sales rose, although costs increased.

Relative Clauses

Type	Commas?	"That" allowed?	Pronoun omission?
Defining (restrictive)	No	Yes	Yes (when object)
Non-defining (non-restrictive)	Yes	No	No

Noun Clauses

Position	Comma?
Subject	No comma before the verb
Object (after verb)	No comma before the clause
Complement (after linking verb)	No comma before the clause

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Reducing Relative Clauses: Quick Patterns

Full Clause	Reduced Form	Method
who/that + active verb	-ing form	The man who is waiting --> The man waiting
who/that + be + -ing	-ing form	The students who are studying --> The students studying
who/that + be + past participle	past participle	The report that was written --> The report written
who/that + be + adjective	adjective	The options that are available --> The options available
who/that + be + prepositional phrase	prepositional phrase	The keys that are on the table --> The keys on the table

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Common Mistakes: Checklist

Use this checklist when editing your writing. Each item targets a frequent error covered in this module.

Sentence Structure

• No fragments. Every dependent clause is attached to an independent clause.
• No double conjunctions. Each pair of clauses has only one connector (although...but, because...so are errors).
• Noun clause word order. Embedded questions use statement order (subject + verb), not question order.

Punctuation

• Comma after introductory dependent clauses. If the sentence starts with because, although, when, if, etc., there is a comma before the independent clause.
• No unnecessary comma before because. When the independent clause comes first, do not add a comma before because (unless needed to prevent misreading).
• Defining relative clauses have no commas.
• Non-defining relative clauses have commas on both sides.
• No comma before that-clauses after reporting verbs. (She said that... not She said, that...)
• No comma between a noun-clause subject and its verb. (What he said was true not What he said, was true)

Relative Clauses

• "That" only in defining clauses. Never use that after a comma.
• "Who" for people, "which" for things. Never use who for things or which for people.
• "Whose" not "who's." Whose = possession; who's = "who is" or "who has."
• No duplicate pronoun. Do not write the book which I read it -- the relative pronoun replaces the pronoun.

Conjunctions

• "Whether" (not "if") for subject noun clauses and after prepositions.
• "Since" and "as" are unambiguous. If the meaning could be either cause or time, choose a more specific conjunction.
• "Unless" means "except if." Do not use unless when you mean if.

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Sentence Patterns at a Glance

These are the core complex sentence patterns. Every complex sentence you write will follow one of these structures.

Pattern	Structure	Example
Adverbial (front)	DC, IC	When the bell rang, everyone stood up.
Adverbial (end)	IC DC	Everyone stood up when the bell rang.
Defining relative	IC [who/that/which...]	The students who arrived early got the best seats.
Non-defining relative	IC, [who/which...],	Dr. Lee, who joined last year, leads the project.
Noun clause (subject)	[What/That/Whether...] + VP	What she discovered changed the field.
Noun clause (object)	S + V + [that/what/whether...]	I believe that the plan will succeed.
Noun clause (complement)	S + linking V + [that/what...]	The issue is that we lack funding.
Reduced relative	NP + participle/adj/PP	The data collected last year supports the theory.

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Final Editing Strategy

When revising a piece of writing for complex sentence quality, follow this four-step process:

1. Check for fragments. Scan for any dependent clause standing alone as a sentence. Every subordinator, relative pronoun, or noun-clause starter must lead to a complete sentence containing an independent clause.

2. Check for comma rules. Verify that introductory dependent clauses are followed by commas, that defining relative clauses have no commas, and that non-defining relative clauses have commas on both sides.

3. Check for variety. Are you using the same subordinating conjunction repeatedly? Vary your connectors: swap because for since or given that; replace although with even though or while. Mix relative clauses with adverbial clauses and noun clauses.

4. Read aloud. If a sentence feels awkward or overly long, consider splitting it. If a series of short sentences sounds choppy, look for logical relationships and combine with subordination. The goal is a natural rhythm that guides the reader smoothly from one idea to the next.