11. What good time we had last night!
12. We shall spend three-day holiday together.
13. I came to understand that was not easy to earn money.
14. Some parents think useless for girls to go to school.
15. When he bought a chocolate cake, he put them in a secret place.
16. One day I wrote a little story and showed to my teacher.
17. It’s important that we should think over before doing anything.
18. The truck was moving so fast that the driver couldn’t control.
19. I apologized and controlled me at my best till the dinner started.
20. We must take part in the social practice to prepare us well for our future.
参考答案：11-15 a good time; a three-day; that后加it; think后加it; them-it;16-20 showed后加it; think后加it; control后加it; me-myself; us-ourselves;