Đáp án:

1. If we pollute the air, we'll have breathing problems.

2.Because it's raining very hard, we cancel our picnic.

3. Although he was sick, he did the exam very well.

4. want to have a park view in the front of the house and have a mountain view in the back.

5. Unless we try to save our sources of energy, they'll soon end.

13. Serious newspapers are more expensive than popular newspapers.

6. We haven't got enough glasses for everybody to have a drink.

8.This is the first time I have seen a beautiful sight.

14. You needn't have finished your assignment this evening.

9. My sister will be eighteen next week.

10.Charles doesn't live far from his house.

11.The doctor said that unless my father stopped smoking, he would be ill.

7.Mike doesn't play chess as well as Barbera.

12.Do you take an interest in astronomy?

1/ If we pollute the air, we'll have breathing problems.

2/ Because it's raining very hard, we cancel our picnic.

3/ Although he was sick, he did the exam very well.

4/ I want to have a park view in the front of the house and have a mountain view in the back.

5/ Unless we try to save our sources of energy, they'll soon end.

6/ We haven't got enough glasses for everybody to have a drink.

7/ Mike doesn't play chess as well as Barbera.

8/ This is the first time I have seen a beautiful sight.

9/ My sister will be eighteen next week.

10/ Charles doesn't live far from his house.

11/ The doctor said that unless my father stopped smoking, he would be ill.

12/ Do you take an interest in astronomy?

13/ Serious newspapers are more expensive than popular newspapers.

14/ You needn't have finished your assignment this evening.