Bài 11. Hoàn thành các câu sau, chọn và cho dạng đúng của các độn từ cho sẵn.

happen

Reduce

save

suffer

Cause

throw

Take

be

change

See

1. If we use less vehicles, we _________ the amount of carbon dioxide into the air.

2. If you __________ the president, what you do to prevent air pollution.

3. If there were no fresh water left, what ____?

4. If people (not) ________________ rubbish in the street, it would look better.

5. if there wasn’t so much light in the cities at night, we __________ the starts more clearly.

6. If the water is contaminated, people ________ from many diseases.

7. If chemicals from factories are dumped into rivers and lakes, they ______ water pollution.

8. If people want to protect their planet, they should ________ their habit of using plastic bag for convenience.

9. If we recycle paper, we ________ 1000 trees a day.