what

• 疑问词，用于询问不限定范围内的人、事物、动作或性质。可用于提问身份、种类或数量。

An interrogative determiner used to ask for information specifying something from an open or indefinite set. It is also used in exclamations to express surprise or emphasis.

1. Interrogative selection (open set)A1formal

   Used in questions to ask for information about a specific thing, person, or idea when the possible answers are not limited to a known set. It implies 'which one(s) among all possibilities'.

   疑问选择（开放集合）

   • What time is it?
   • What color do you like?
   • What books did you buy?

2. Exclamatory emphasisA2informal

   Used in exclamations to express strong emotion, such as surprise, admiration, or shock, regarding the quality or nature of something.

   感叹强调

   • What a beautiful day!
   • What nonsense!
   • What an idea!

3. Relative reference (free relative)B1formal

   Used to introduce a noun clause that functions as the subject or object of a sentence, meaning 'the thing(s) that'.

   关系指代（自由关系从句）

   • I know what you mean.
   • What he said was true.
   • Do what you want.