Стр. 66, упр. 2 b)

• increase
• melt
• fuel
• emission
• to reduse
• to rise

Стр. 66, упр. 2 c)

1. pollution in the past;
2. pollution now;
3. greenhouse effect;
4. global warming;
5. carbon footprint;
6. ozone depletion and melting the ice;
7. international agreements.

Стр. 66, упр. 2 d)

The pollution situation is changing for the worse nowadays.

Стр. 67, упр. 3 a) b)

1. The first sentence represents unreal present and Conditional II is used here.
2. The second sentence represents unreal past and Conditional III is used here.
3. The third sentence represents real future and Conditional I is used here.

Стр. 67, упр. 3 с)

1. The word 'would' is used.
2. The word 'if' is used.
3. The meaning of the sentence doesn't change if you change the order of the clauses.
4. No, the comma is put only after a conditional clause.
5. Conditional III tells us about lost opportunity.

Стр. 67, упр. 4

1. Hadn't increased, would have started.
2. Hadn't released, would have become.
3. Hadn't cut down, would have released.
4. Hadn't cut down, would have absorbed.
5. Hadn't started, wouldn't have appeared.
6. Would have made, had produced.

Стр. 68, упр. 5 a)

1. If humans hadn't made progress, they wouldn't have moved to the cities.
2. If they hadn't moved to the cities, industries wouldn't have developed.
3. If industries hadn't developed, cities wouldn't have grown in population.
4. If cities hadn't grown in population, cities wouldn't have grown in size.
5. If cities hadn't grown in size, people wouldn't have needed more electricity.
6. If people hadn't needed more electricity, industries wouldn't have grown.
7. If industries wouldn't have grown, more fuels wouldn't have been burned.
8. If more fuels hadn't been burned, more greenhouse effect wouldn't have been produced.
9. If more greenhouse effect hadn't been produced, more heat wouldn't have been accumulated in the atmosphere.
10. If more heat hadn't been accumulated in the atmosphere, the temperature of the Earth wouldn't have risen.
11. If the temperature in the Earth hadn't been risen, humans wouldn't have damaged the Earth.
12. If humans hadn't damaged the Earth, humans wouldn't become an endangered species.