/Relative Clauses
B1Relative Clauses

Which or That

1

What is it?

Both "which" and "that" can introduce relative clauses referring to things. The choice depends on whether the clause is defining (identifying) or non-defining (commenting). "That" is only used in defining clauses. "Which" can be used in both, but is the only option in non-defining clauses. After prepositions, "which" is always used.

2

How to form it

SubjectPositiveNegativeQuestion
Defining clause — "that" or "which"The car that/which I bought is blue.The book that/which I didn't finish is still on the shelf.Is this the report that/which you wrote?
Non-defining clause — "which" onlyThe car, which I bought last year, is blue.The report, which wasn't ready on time, caused problems.
After a preposition — "which" onlyThe town in which she grew up is small.The deal over which they argued was cancelled.
Referring to a whole clause — "which"She passed her exam, which was a great surprise.
  • • In DEFINING clauses: use "that" or "which" — both are correct, but "that" is more common in everyday speech.
  • • In NON-DEFINING clauses (with commas): use "which" ONLY. NEVER use "that".
  • • "That" is NOT used after a preposition. Use "which": "the firm for which he worked" (formal).
  • • "Which" can refer back to a whole previous clause: "She cancelled the meeting, which annoyed everyone."
  • • In American English, "that" is strongly preferred in defining clauses.
  • • "That" is also used after superlatives: "It's the best film that I've ever seen."
3

When to use it

  1. 1

    "That" in defining clauses for things

    This is the key that opens the back door.

  2. 2

    "Which" in non-defining clauses

    The new library, which opened last month, is very popular.

  3. 3

    "Which" after prepositions

    The committee on which she sits voted against the proposal.

  4. 4

    "Which" to refer to a whole idea

    He arrived late, which meant we missed the start.

  5. 5

    "That" after superlatives and "all/the only/the first"

    This is the first film that has made me cry.

4

Common mistakes

My laptop, that I bought in 2020, still works perfectly.

My laptop, which I bought in 2020, still works perfectly.

"That" cannot be used in non-defining relative clauses (those with commas).

The project in that she was involved was a success.

The project in which she was involved was a success.

"That" cannot follow a preposition. Use "which" after prepositions.

She got the job, that made her very happy.

She got the job, which made her very happy.

To refer back to a whole clause, use "which", not "that".

5

Quick reference

  • Defining clause: "that" or "which" (both OK for things).
  • Non-defining clause: "which" ONLY (never "that").
  • After a preposition: "which" only.
  • Referring to a whole clause: "which" only.
  • "That" is preferred after superlatives and "all/the only/the first".
  • Non-defining clauses are marked by commas.
6

Natural conversation example

Two colleagues discuss a work presentation.

N

Nina

The slide that you prepared for the opening was very effective.
J

Jay

Thanks. I also added the data which the client sent yesterday.
N

Nina

The chart, which I think is on slide five, was really clear.
J

Jay

I used the template that the design team made last year.
N

Nina

Everything went smoothly, which was a relief after all that preparation.
J

Jay

The feedback that we received was mostly positive.
N

Nina

The one thing that I'd change is the font on the final slide.
J

Jay

The conclusion, which I wrote at the last minute, could definitely be stronger.

Practice Exercises

Fill in "which" or "that". In some cases, both are possible — write both.

  1. 1.
    The computer __ I use for work is very old.
  2. 2.
    The Eiffel Tower, __ is in Paris, is over 300 metres tall.
  3. 3.
    The best film __ I've ever seen is very old.
  4. 4.
    She lost her job, __ surprised everyone.
  5. 5.
    The tool __ we need is in the cupboard.
  6. 6.
    His new album, __ came out last week, is fantastic.
  7. 7.
    It was the only solution __ worked.
  8. 8.
    The contract in __ clause 4 appears needs revising.
  9. 9.
    All the feedback __ we received was positive.
  10. 10.
    They extended the deadline, __ was very helpful.
Dropping the Relative PronounAll TopicsWhere or That

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