関係代名詞 what
I could not understand what she said.
Is that what he wants?
Will you please tell me what you know about her?
This is what she said.
What she saw there was surprising.
What they did was wrong.
What I didn't expect happened.
What you have to do is (to) go to bed early.
What your parents want you to do is (to) contact them more often.
What that boy says is different from what he does.