5. Look,there is a bird on the       (树枝) of this tree.

3. The students       (讨论) the problem with their teachers yesterday.

4. We all know the       (重要性) of water.

1. The scientists are doing something to        (極救) the earth.

2. There are many kinds of       (松树) in this park.

5. Try to eat at least one piece of        (fruit) a day.

6. Go slowly and        ( breath) slowly.

3. 我们周围许多有用的东西都来自树木。

Many useful things around us                    .

2. 妈妈每天都进行打扫以保持房间干净整洁。

Mum does the cleaning every day to                            and tidy.

1. 我们在许多方面都有同样的想法。

We have the same ideas                    .

22. 在你的头脑中      

23. 充满      

19. 停止做某事      

20. 对……有用,有好处      

21. —个主要的问题      

16. 保持凉爽      

17. 有害气体      

18. 从……中得到……