1. If the air is so dirty, I will sneeze so much
2. Because of the polluted water, we cannot swim in this river
3. If he smokes, he will be sick
4. The principle is proud of the students in grade 9 because they're good helpers
5. If you don't smoke in public places, you'll be fined
6. In spite of his sickness, he did well in the exam
7. The Browns have not painted the living room for two years
8. If there is a screen on the window, there won't be so many bugs in the room
9. If he is busy, he can't help them
10. Unless she has enough money, she can't buy the house
11. Should he came here tomorrow, he may be shocked
12. If she doesn't hurry, she will miss the train.