1. don't have to (do sth.) (不必干某事)
2. lay, lie的用法
3. fall off (跌倒; 减少)
4. knock off (one's feet) (把...击倒)
5. deal with (对付; 处理)
6. throw up (呕吐)
7. mouth-to-mouth (嘴对嘴)
8. out of one's reach (够不着)
9. ought to (应该)
10. pay attention to (注意)
11. take it easy (别紧张)
12. by mistake (弄误会)
13. hold up (举起)