根据下列句子及所给单词的首字母或中文解释，写出该单词的正确形式。
1. To get full marks in the exam is really a c_________ task for little Jack.
2. The club is for t_________ who are between 13 and 19 years old.
3. You can't ask a lady about her age in public because it will make her e_________.
4. One of the side e_________ of this drug is the easiness of habit-forming.
5. Jack is r_________ from his operation and he will soon go back home.
6. Bill Gates _________ (捐赠) lots of money to poor people every year.
7. The famous professor gave us an _________ (解释) of how sound travels in water.
8. The final exam is coming and everyone is making _________ (准备) for it.
9. Mary looks _________ (苗条) than Helen.
10. Children are _________ (禁止) to smoke.