根据所给中文或单词写出正确的形式：
1. He _________ (重) about four kilograms when he was born.
2. He didn't pass the exam because he was too _________ (认真的).
3. He is very young, so he can't look after _________ (自己).
4. The doctor saved many people's _________ (生命).
5. Do you know that he is fond of _________ (收集) stamps?
6. There are lots of _________ (老鼠) in the old man's house.
7. Sandy's sister _________ (刷) her cat's fur once a day.
8. He wants to be a _________ (科学家) when he grows up.
9. I wanted to see the rainbow after the rain. But it didn't _________ (出现).
10. When I woke up at six, I heard somebody _________ (敲) on my door.
11. It's _________ (危险的) for you to cross the road when the lights are red.
12. I look forward to _________ (own) a computer.
13. ________ Julie ________ (feed) her pet last night? Yes.
14. Shall we go _________ (row) tomorrow? A good idea.
15. Mr. Wang _________ (find) a job in a big city two years ago.
