Đáp án:

1. Someone saw him pick up the gun. -> He was seen to pick up the gun by someone. hoặc: He was seen picking up the gun.

2. He has caught a lion and shot 2 others. -> A lion has been caught by him and 2 others have been shot.

3. He received a letter from home by the evening post. -> A letter from home was received by him by the evening post.

4. I put the 5 pound note into one of my books yesterday. -> The 5 pound note was put into one of my books yesterday.

5. After he had told a story, we clapped our hands. -> After a story had been told by him, we clapped our hands.

6. His wife usually brings him sandwiches at lunch time. -> He is usually brought sandwiches at lunch time by his wife.

7. They were continually asking questions. -> Questions were continually being asked by them.

8. We have to pick fruit very early in the morning. -> Fruit has to be picked very early in the morning.

9. She decided to paint her house blue. -> It was decided by her to paint her house blue. hoặc: Her house was decided to be painted blue.

10. My classmates used to call me John. -> I used to be called John by my classmates.