41. cover v. 覆盖 n. 封面
42. symbol n. 符号
43. flow v. 流淌
44. stream 小溪
Phrases:
1. turn that tap off 把水龙头关上
2. sound impatient 听起来不耐烦
3. a drop of water 一滴水
4. float comfortably 舒服地飘浮
5. enjoy the view 欣赏风景
6. the Yangtze River 扬子江
7. travel a long way 走了好长一段路
8. get cleaned up 变得彻底清洁
9. sound puzzled 听起来很困惑
10. a water treatment works 一个水加工厂
11. a thorough cleaning 一次彻底的清洗
12. a few chemicals 几种化学物质
13. chemistry lesson 化学课
14. a sewage plant 一个污水处理厂
15. in the first place 首先, (一开始的时候)
Unit 3 A dangerous servant
New words: