现在完成时:
have/has + v-ed (过去分词)
(1) I have worked Have I worked?
I have not worked Have I not worked?
He (she, it ) has worked Has he (she, it ) worked?
He (she, it) has not worked
Has he (she, it ) not worked?
(3) We have worked Have we worked?
We have not worked Have we not worked?
(4) You have worked Have you worked?
You have not worked Have you not worked?
(5) They have worked Have they worked?
They have not worked Have they not worked?
e.g. Have you ever seen the sea?
He has gone to the library .
I have lived here for more than thirty years.
I’ll wait until he has written his letter.
They often play chess after they have had supper.