知识点
一、重点短语:
1. be full of 充满
2. close down 关闭
3. play a part in 扮演角色
4. clean up 打扫卫生
5. cut down 减少
6. instead of 代替
7. make a difference 起作用，有影响
8. used to 过去常……
9. lead to 通往……
10. hear of 听说
11. be harmful to …对……有害
12. the food chain 食物链
13. at the top of 在……顶部或顶端
14. turn off 关掉
15. take part in 参加
16. pay for 付费；付出代价
17. take action 采取行动
18. throw away 扔掉；抛弃
19. put sth. to good use 好好利用某物
20. pull…down 拆下；摧毁
21. turn upside down 上下颠倒；倒转
22. set up 建起，成立
23. bring sb. Back to 使想起
24. be known for 因……而闻名
二、重点句式：
1. It used to be so clean. 它过去是那么干净。
2. Everyone in this town should play a part in cleaning it up. 我们镇上的每个人都应该尽一份力把这条河清理干净。
3. The air has become really polluted around here. 这附近的空气被严重污染了。
4. To cut down air pollution, we should take the bus or subway instead of driving. 为了减少空气污染， 我们应该乘公汽或地铁，而不要开车。
5. It doesn’t cost anything. 它不耗费任何东西。
6. But in fact, around 70 millon sharks are caught and traded in this industry every year. 但事实上，每年大约七千万条鲨鱼被抓来用作商业交易。
7. The numbers of some kinds of sharks have fallen by over 90 percent in the last 20 to 30 years. 有些种类的鲨鱼数量在过去的二三十年里，下降了百分之九十以上。
8. So far, no scientific studies have shown that shark fins are good for health, so why eat them? 到目前为止，没有科学研究证明显示鱼翅对健康有益， 所以为什么要吃呢？
9. Recycling paper is really easy. 回收再利用纸很容易。
10.But it’s hard to stop riding in cars. 但是停止开小汽车是很难的。
11.We shouldn’t use paper napkins . 我们不该用餐巾纸。
12.Turn off the lights when you leave a room. 当你离开房间时关掉灯。
13.Have you ever thought about how these things can actually be put to good use？ 你曾经考虑过怎样能充分利用这些东西吗？
14.Amy isn’t the only one who is good at recycling. 艾米并不是唯一善于回收利用的人
15.She has been doing this for a few years now. 她做这事已经有好几年了。
16.Not only can the art bring happiness to others，but it also shows that even cold，hard iron can be brought back to life with a little creativity. 艺术不仅能带给别人快乐，而且也说明了只需要一点创造力，即使是冰冷、坚硬的铁也可以产生活力。
巧记歌诀：
1. “花费”用法口诀
花费四词各家聚，认准人物谁主语；
in，on就跟spend去，
for在pay后不客气；
cost物前人后移，
It takes…to do在一起。
2. 被动语态
宾变主，主变宾，
by短语后面跟，
谓语动词变被动，
be后“过分”来使用。
