嚴格按照時態和句意改成被動的答案應該是：
1. Machines are made by them in that factory.
2. The stamps will be shown to me by him.
3. Have many buildings been built by the workers in the city?
4. What the boys are often told to do by the teacher?
5. The dictionary was not given to me by him yesterday.
6. The bike isn"t being mended by them in that shop.
7. They saw something be stolen by the boy in the supermarket.
8. The free umbrellas can be used by everyone.
9. Trees had better be planted on the hill.
10. He will be made to finish his homework by us.正規英文寫作裡極少用被動句。以上的題目太牽強，寫成被動特別扭。這純粹是“中國式英語”，目的大概只是考察語法。
嚴格按照時態和句意改成被動的答案應該是：
1. Machines are made by them in that factory.
2. The stamps will be shown to me by him.
3. Have many buildings been built by the workers in the city?
4. What the boys are often told to do by the teacher?
5. The dictionary was not given to me by him yesterday.
6. The bike isn"t being mended by them in that shop.
7. They saw something be stolen by the boy in the supermarket.
8. The free umbrellas can be used by everyone.
9. Trees had better be planted on the hill.
10. He will be made to finish his homework by us.正規英文寫作裡極少用被動句。以上的題目太牽強，寫成被動特別扭。這純粹是“中國式英語”，目的大概只是考察語法。