what is a relative pronoun that includes its antecedent (= the thing(s) which) and forms a noun clause. Let us also organize its idiomatic expressions.
Basic Rules
what = the thing(s) which: It contains its antecedent. The entire clause functions as a noun (subject, object, or complement).
“What he said was true.” ← Subject
“Tell me what you want.” ← Object
Idiomatic expressions:
- what S is: “what S is now” (personality or present condition) “He is not what he used to be.”
- what is called / what we call: “what is called〜” “He is what is called a genius.”
- what is more / what is worse / what is better: “in addition / worse still / better still”
- A is to B what C is to D: “The relationship between A and B is the same as that between C and D”
What I need most is a good night's sleep.
He is what is called a self-made man.
Reading is to the mind what food is to the body.
Points to Note
① Difference between what and which: which requires an antecedent. what includes its antecedent. If the antecedent is explicitly stated, use which; if it is not, use what.
② what + adjective: “what little money I have” (all the small amount of money I have), with the nuance of “all of the little〜.”
③ Structure of A is to B what C is to D: It expresses a proportional relationship.
- what = the thing(s) which (includes its antecedent)
- what S is: S's present condition or personality
- what is called: so-called〜
- what is more/worse/better: in addition/worse still/better still
- A is to B what C is to D: the relationship between A and B is the same as that between C and D
Practice
- Translate “Please believe what he said” into English using what.
- Translate “She is what is called a genius” into English using what is called.
- Translate the following into English: He lost his job, and, what is worse, his health began to fail.