1 Rubbish makes the streets and rivers dirty. To keep the streets and rivers clean, we can .
2 Smoke from cars makes the air dirty. To keep the air clean, we can for short trips.
3 To help keep the air clean, we can also .

1 b 2 a 3 c

1 Yugong wanted to move the two mountains from his home.
2 There are many flowers and trees. They keep the fresh.
3 A lot of is in the river and so many fish are dead.
4 My grandpa always keeps his house and tidy.
5 Black smoke from cars makes the air .

1 away 2 help, air 3 rubbish 4 clean 5 dirty

F Read and order(将下列句子排列成一段通顺的对话)
() Oh no! The water becomes black and dirty.
() They’re dumping (倾倒) rubbish into the river.
() Look at the men. What are they doing by the river?
() What should we do now?
() Let’s go and stop them.
() Right! We should also call on people to protect the environment.

3 2 1 4 5 6