13. stringed instrument 弦乐器
14. topmost=highest
15. wretched=very unhappy
16. on behalf of 代表
17. stained with 沾上
18. burst with 充满
Burst into 突然..起来
19. air 风度
Film 薄膜
20.uncertainties
Unit 6
1.strain up 竭力爬坡
strain every nerve to do sth. 不遗余力做
2.scatter 散布在
3.assure
you may rest assure that=I can assure you that
4.as if + to / clause / 分词
5.on the occasion of sth.
On occasion=now and then
6.relate to 关联，理解
in relation to
be relevant to 和..相关