3. Fill in the blanks by choosing the right answer.
1. Environmental protection is an ... problem.
a) easy:
b) important; c) pleasant
2. Factories pour a lot of ... into air and water.
a) a shortage b) waste; c) pollution.
I
3. What caused the ... of wildlife.
a) destruction: b) poison c) population
4. Many rivers and lakes are
a) poisoned: b) filled c) used
5. Many scientists try ecology problems.
a) solve: b) to know: c) to protect