Note: Use the simple past if:
1. The action occurred in the past and
does not include the present.
2. The action happened in specific past time.
Use the present perfect if:
1. The action includes the present.
2. The action occurred in non specific past time.
3. For repeated actions in the past.
4. For adverbs of frequency in actions that include the present time.
1. Mr. and Mrs. Slater (sell) their house several days ago.
2. George Howell (work) for the Ajax Company since 1999.
3. Our instructor (explain) that lesson to us in yesterday's class.
4. The weather (be) terrible ever since last Saturday.
5. We (spend) several weeks in Mexico City last year.
6. Many people in this class (see, never) the famous Grand Canyon.
7. Our friends (return) to Canada a week ago yesterday.
8. Michael (study) English at this school for six months now.
9. I (speak) to Mr. Scott about that matter several times already.
10. Miss Ross (be) in Havana until two months ago.
11. My wife and I (travel) by air many times in the past.
12. My friend Roger (see, never) that television program.
13. Fred and Bill (finish, not) their homework yet.
14. I (have) a little trouble with my car last week.
15. However, I (have) any trouble with it since that time.
16. John (drive) over the Golden Gate Bridge hundreds of times.
17. I (read, already) 187 pages of this new novel.
18. From the time of his arrival until now, he (avoid) that sensitive topic.
19. We (study) practically every lesson in the book so far.
20. The mailman (deliver) the letter just a few minutes ago.
21. That fellow (work) here for the past three weeks.
22. Our teacher (give) us more than four examinations this semester.
23. Formerly, Mr. Foster (work) for the A. B.C. Supply Company.
24. We (have) more than the normal amount of rain so far this year.
25. Before his graduation, Fred's brother (apply) for a job with Apple Computer.
26. Mr. and Mrs. Phillips (live) in Daly City from 1995 to 2002.
27. A little while ago, we (hear) some very bad news.
28. Professor Moore, our English teacher, (write) three textbooks.
29. I (read) that book three or four times when I was in my twenties.
30. The Smiths (go) to Belgium during their vacation.
31. Pierre and Carlos (learn) a lot of English since June.
32. Mr. and Mrs. Benson (fly) to New York twice since last summer.