№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