Відповіді: Стр.60 (4-5)

4. Complete the sentences with if or unless.

1. Polar bears won’t find enough to eat unless we do more to protect their environment.

2. If we don’t protect these animals now, they will die out.

3. Many birds will suffer if sea levels continue to rise.

4. Unless we control whale fishing, there’ll be no whales left soon.

5. Read the examples and the rule. Which example uses the second conditional?

1. If bees disappear completely, we will all suffer. → First conditional.

2. If bees disappeared completely, we would all suffer. → Second conditional.