四.答案
1. have taught
2. using
3. are sweeping
4. weren’t listening
5. to receive
6. have … lived
7. came … didn’t
8. did … see, saw
9. would be used
10. would happen
11. had … left
12. have been built
13. be cleaned
14. was lying
15. was raining
16. was cooking
17. are doing, Don’t make
18. have … beeen, went
19. arrives
20. are made
21. writing
22. be done
23. to choose
24. to learn
25. tells, will tell
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