Kunci jawaban:

1. Mr. Moore has explained those two lessons to us already.

2. We have followed the instructions in the book carefully so far.

3. We have known Mr. and Mrs. Smith for over twenty years.

4. I think Mr. Harris has already had his lunch.

5. Carol and Martha have had lots of practice in English so far.

6. He has already had his lunch.

7. I have never been there before.

8. We have visited that museum already.

9. Mr. and Mrs. Slater have sold their house since two weeks ago.

10. Many people in this class have never seen the famous Grand Canyon.

11. Fred and Bill haven't finished their homework yet.

12. However, I haven't had any trouble with it since that time.

13. She has read 187 pages of this new novel already.

14. We have studied practically every lesson in the book so far.

15. Pierre and Carlos have learned a great deal of English since June.