IV

3. to learn

5. to do

6. to choose

10. chatting

V.

1. had bought

2. was

3. would sell

4. had passed

5. could

6. would sell

7. had gone

8. hadn't done

9. were listening

10. had to

VII

1. being asked 

2. haven't tidied

3. are...speaking

4. lived

5. to be

6. driving

7. to reach

8. get up

9. reading

10. wasn't

23. won't fail

24. have not met

25. visited

26. knew

27. didn't go 

28. go

29. went

30. to be

--

IV.

1. playing

2.repairing

3. learning

4. having

5. to do

6. to choose

7. listening

8. playing

9. reading

10. chatting

--

V.

1. bought
2. came

3. were selling

4. had passed

5. could

6. would sell

7. had go

8. hadn't done

9. was listening

10. had to

--

VII.

1. asking

2. haven't tidied

3. are/ speaking

4. lived

5. to be

6. drive

7. to reach

8. get up

9. reading

10. wasn't

--

VIII.

1. educated

2. Scientists

3. possibility