Grammar practice · Skill 8 of 14

Relative Clauses Exercises: Who, Which, That

A relative clause is a short group of words that describes a noun. It usually starts with a relative pronoun: who, which or that. Get it right by matching that word to the noun and never repeating the noun inside the clause. Seven rules and 40 exercises below take you from the basics to the common traps.

40 questions 8 levels of 5 7 rules Level 1 free

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What we measured

of 28,077 sentence-building answers using relative clauses were wrong in the last six months.

How do you use who, which and that?

Who for people, which for things, that for both

A relative clause describes a noun, and the word that opens it points back to that noun. Use who for people and which for things. That works for both when there is no comma before it, and American writers usually prefer it for things. Never use what right after a noun: "the book what I need" is always wrong.

Right:A student who asks questions learns faster.
Right:We need a printer that works.
Right:The counselor that I saw was very kind.

Not:The woman which helped me was kind.Instead:The woman who helped me was kind.
Not:The notebook what I need is at home.Instead:The notebook that I need is at home.

Do not repeat the noun inside the clause

Who, which and that already stand for the noun, so they take the place of a word such as it, him or them. Do not keep that word as well. Write "the song that I heard," not "the song that I heard it." The same is true after a small word such as to or with: "the classmate who I study with," not "with her."

Right:The paper that I wrote is on my desk.
Right:The roommate who I live with is from Texas.

Not:The show that we saw it was long.Instead:The show that we saw was long.
Not:The coach who I met him was helpful.Instead:The coach who I met was helpful.

The verb matches the noun before who

When who, which or that does the action in its clause, the verb takes its form from the noun right before it: a student who studies, students who study. Then check the main verb of the sentence. It matches the noun the sentence is about, not the noun closest to it: the students who live near the lake are lucky.

Right:My aunt, who runs a cafe, works every weekend.
Right:Courses that meet at night are often full.
Right:The tutor who helps these students is excellent.

Not:A person who exercise often feels better.Instead:A person who exercises often feels better.
Not:The students who live near the gym is lucky.Instead:The students who live near the gym are lucky.

Whose for belonging, where for places, when for times

Use whose in place of his, her, its or their: a classmate whose car broke down. It works for things as well as people. Use where and when only if the clause is already complete. Test it with "there": we eat there, so "the room where we eat." But we use it, so "the room that we use." Formal writing sometimes says in which instead of where.

Right:That is the cafe where I met my roommate.
Right:Friday is the day when the report is due.
Right:We read about a town whose river had dried up.

Not:I know a student who his father is a pilot.Instead:I know a student whose father is a pilot.
Not:The gym where we use is closed.Instead:The gym that we use is closed.

Commas mark extra information

Ask whether the clause tells you which one. If it does, it is necessary, so use no commas: the students who finished early can leave. If you already know which one, the clause is only extra information, so put commas around it: my mother, who lives in Ohio, called me. After a comma, use who, which or whose, never that. Names almost always need the commas.

Right:Dr. Lin, who teaches physics, is my advisor.
Right:Students who arrive late cannot enter.
Right:Boston, which has many colleges, is popular with students.

Not:My dorm, that opened in 2020, is quiet.Instead:My dorm, which opened in 2020, is quiet.
Not:People, who exercise, sleep better.Instead:People who exercise sleep better.

Drop who, which or that only before a new subject

Look at the word right after who, which or that. If it is a new subject, meaning a new doer such as I, we or the professor, you may drop the word: the book (that) I bought. If it is a verb, the word must stay: the student who won. It must also stay after a comma, even when a new subject follows.

Right:The book I bought was cheap.
Right:The student who won the prize is my lab partner.
Right:My car, which I bought in May, needs new tires.

Not:The student won the prize is my lab partner.Instead:The student who won the prize is my lab partner.
Not:My car, I bought in May, needs new tires.Instead:My car, which I bought in May, needs new tires.

Join two short sentences into one

Two short sentences about the same noun can often become one. Find the shared noun, swap the second mention for who, which, that or whose, and place the clause right after the noun it describes. "I know a woman. She teaches chemistry." becomes "I know a woman who teaches chemistry." A clause attaches to the noun just before it, so keep the two side by side.

Right:I know a woman who teaches chemistry.
Right:We toured a lab that studies bees.
Right:I have a friend whose brother plays the cello.

Not:I know a woman who she teaches chemistry.Instead:I know a woman who teaches chemistry.
Not:I gave the charger to my friend that I borrowed.Instead:I gave the charger that I borrowed to my friend.

Where this costs you marks on the TOEFL

Grammar is not tested as its own section on the TOEFL. Relative clauses count inside Writing and Speaking instead. Build a Sentence makes up 10 of the 12 Writing items, and the middle of a relative clause is a common place for word order to fall apart. In Write an Email and the Academic Discussion, the risk is different: a response made only of short, simple sentences sounds basic, even with no errors. Joining two ideas with who, which or whose shows that you can build longer sentences with control. In the Interview, the same skill lets you add a detail without stopping to start a new sentence.

If your first language is...

First language	What to watch for
Arabic and Persian speakers	Arabic normally keeps a small pronoun inside the clause, so word for word it says "the book that I read it." Persian does the same in some sentences, especially after a preposition. Standard English does not. Once you have written who, which or that, delete the extra him, her, it or them.
Chinese, Japanese, Korean, Turkish, Tamil and Telugu speakers	In your language the description comes before the noun, as in "the I-read book." English reverses this. Say the noun first, then add the clause right after it: the book that I read. Building the sentence in that order gives who, which or that a clear place to go.
Hindi and Urdu speakers	Your languages often link two parts with a pair of words, jo and vo, which feels like "which book I read, that one is good." English uses one link only. Put the clause straight after the noun and drop the second pointer: the book that I read is good.
Spanish, Portuguese, French, Russian and Polish speakers	Your language uses the same relative word for people and things, so "the teacher which helped me" can feel fine. English needs who or that for people. Russian and Polish speakers also put a comma before every such clause. In English, use no comma when the clause tells us which one.

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Relative clauses exercises: Level 1 with answers

Try these before you open an answer. Each one explains why, not only what.

I know a teacher _____ speaks three languages. (who / which / where)
Show the answer
who
A teacher is a person, so use who. Which is only for things, and where is for places.
This is the bus _____ goes to the airport. (who / which / where)
Show the answer
which
A bus is a thing, so use which. That would also work here, but who is only for people.
Find the mistake: The man which fixed my bike was very friendly.
Show the answer
The man who fixed my bike was very friendly.
A man is a person, so use who or that. Which is only for things.
I have a friend _____ lives in Chicago.
Show the answer
who
A friend is a person, so use who. That is also correct here because there is no comma.
Put in order, with one piece left over: She bought a phone [great / who / takes / that / photos].
Show the answer
She bought a phone that takes great photos.
A phone is a thing, so use that, not who. The clause goes right after phone, the noun it describes.

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FAQ

Common questions

What is a relative clause?

A relative clause is a group of words that describes a noun and comes right after it. It usually opens with a relative pronoun: who, which, that or whose. In "the student who sits by the window," the clause tells us which student. It has its own verb, but it cannot stand alone as a sentence.

What is the difference between which and that?

With no comma, both can describe things, and American writers usually prefer that: the course that I chose. After a comma, only which is correct: Biology 101, which meets on Mondays. That also works for people when there is no comma, but which does not. If you are unsure, use that with no comma and which with a comma.

Should I use who or whom?

Use who when the person does the action: the tutor who helped me. Whom is for the person receiving the action, as in the tutor whom I hired. In everyday English, who is also accepted there, and you can often drop the word: the tutor I hired. Right after a preposition in formal writing, use whom: the tutor to whom I wrote.

When can I leave out who, which or that?

Look at the word right after it. If a new subject follows, such as I, we or the professor, you can usually leave it out: the book I bought. If a verb follows, you must keep it: the student who won. Keep it after a comma too, because a clause of extra information always needs its opening word.

Do relative clauses help my TOEFL score?

They can, as long as you use them with control. A mix of short and longer sentences sounds stronger than a list of simple ones. Aim for a few natural relative clauses, not one in every sentence. A clear, correct clause is worth more than a long one that breaks.

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