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.