I understand that we use which when options are limited and what when there is no limitation. Check this sentence:

  1. Tell me about things what make you angry.

Is this sentence ok, or is which necessary? Or one more example:

  1. These are things which you wanted.

I can hear that using what is wrong, but why?

  • Just because which and what work as a pair in one situation, does not make them substitutes everywhere. Both examples call for the word that here. Dec 14, 2023 at 14:21
  • 1
    The contrast between "what" and selective "which" apples to interrogative clauses, not relative clauses like the ones in your examples. 1. is ungrammatical because "what" is not a relative pronoun: "that" or "which" is required. 2. is OK.
    – BillJ
    Dec 14, 2023 at 14:34

1 Answer 1


#1 is incorrect.

Both examples have a defining relative clause.

As the relative clauses describe things, we use the relative pronoun which, or the relativiser that in the two cases here as these are defining relative clauses.

In #2, the which/that can be omitted as it is the object of the relative clause.

I rewrite the two sentences, with the words in parentheses being optional.

Tell me about things which/that make you angry.

These are [the] things (which/that) you wanted.

What is not a relative pronoun and cannot be used in this manner.

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