№1

1)      Millions of trees in the Brazil rainforests have been cut down by agricultural workers.

2)      A lot of rubbish was dumped into the sea last year.

3)      A lot of waste is being pumped into rivers by factories.

4)      Many people are annoyed with loud motorbikes.

5)      A new airport is going to be built here next year.

№2

   1)   Had been cleaned

   2)  Will be built

     3) Are polluted

   4)  Was dropped

     5) Is made

№3

1) can

2)should

3)should

4)could

5)can't

6)have to

7)ought to

8)don't have to

9)may

10)may

№4

1)would swim

2)will never know

3)hadn't encouraged

4)woudn't have sent

5)had acted

6)tells

7)would help

8)were

9)will understand

10)will succeed