Choose the best answer to complete each of the following sentences:
1. The dealth rate would decrease if hygienic conditions ........... improved
→ Đáp án: A. were
2. The education in Japan .... if the basic principles of education had not been taken into consideration
→ Đáp án: D. had gone down
3. If there ......, the rice fields could have been more productive
→ Đáp án: A. had been enough water
4. The patient could not recover unless he ....... an operation
→ Đáp án: C. underwent
5. If she ... him, she would be very happy
→ Đáp án: D. should meet
6. If he ...... a thorough knowledge of English, he could have applied for this post
→ Đáp án: A. had had
7. If I had enough money, I .... abroad to improve my Ennglish
→ Đáp án: B. would go
8. The bench would collapse if they ....... on it
→ Đáp án: A. stood
9. If it ...... convenient, let's go out for a drink tonight
→ Đáp án: D. were
10. If you ....... time, please write to me
→ Đáp án: A. have
