用所给动词的适当形式填空。

1.—Hello! Have you _________ (see) my pen? I can't __________ (find)it．

   —I'm afraid I haven't.

2.—Excuse me. Have you _________ (see) my pen? I _________ ( put) it on the shelf a moment ago.

   —Oh, yes, I have. I'm sorry I forgot to _________ (give) it back to you.

3.—Mary, I've _________ (lose) my cap. Have you _________ (see) it anywhere?

   —Look! It's over there. I _________ (see) you put it there.

4.—Have you _________ (find) your knife yet?

   —Not yet.

5.—John, _________ you _________ (return) my pen yet?

   —Not yet. Don't worry! I _________ (return) it soon.

6.—Jim, _________ you _________ (write) a letter to your aunt?

   —Yes, I _________．

   —When _________ you _________ (write) it?

   —I _________ (write) it last week.