How to judge conjunctions like which what

1. what

It is often found in object clauses and subject clauses in noun clauses.

In the object clause what often acts as an object component in the clause. For example: i can't listen to what you said.

The subject clause what is also often seen as an object component. Such as: what she said encouraged me a lot, I should study hard

2. which

In addition to the interrogative sentence, which often appears in the definite clause. When used as an object in a definite clause, it can be omitted. It cannot be omitted when it is used as the subject, and when which is the subject of the clause, the antecedent can only be a thing.

3. that

That is more common in object clauses, definite clauses, copositional clauses and other sentence patterns.

The object clause that can be omitted as a conjunction.

What is used when referring to something in general. Such as: I wonder what you are going to buyI don't know what you want to buy?

Which means something concrete. Such as: in front of the counter selling mobile phones:

i wonder which ( mobile) you are going to buy.I don't know which (phone) you want to buy.

which only takes this thing.

What refers to content.

What can guide the noun clause, and can be used as the subject, object, and predicate in the clause.

Which is a relative pronoun that guides the definite clause, and can act as the subject, object, and predicate in the clause. The words that guide the definite clause are divided into relative pronouns (which, that, whom, whom, whose, as) and relative adverbs (when, where, why), note: there is no what

Let's make a simple note: the definite clause is placed after the noun that means "thing", and the relative pronoun acts as a sentence component in the clause, which is used. If it's not a definite clause, consider using what.

For example: is the book which I talked about yeasterday

which leads the definite clause to be placed after the noun book to modify, which acts as the object of talk about in the clause).

2. this book is what i talked about yesterday.(What leads the noun clause, placed after is, and what acts as the object of talked about in the predicative clause (noun clause). )

which can lead the definite clause what can only lead the interrogative sentence can not lead the definite clause .

In Chinese, it's pretty much the same, if it's a multiple-choice question, use which, and if it's a question-and-answer question, use what.