6. B (economic growth: Tăng trưởng kinh tế)

7. C (migrant: chỉ người di cư với mục đích tìm công việc)

8. B (population: dân số)

9. C (câu điều kiện loại 3)

10. C (câu điều kiện loại 2)

11. A

12. D

13. B

IV/

1. B (were => had been)

2. D (will be => is)

3. A (will make => make/ have to make)

4. A (could had => could have)

5. B (has => had)

V/

1. walked 

2. can/will understand

3. wouldn't have been

4. complains

5. would understand

6. had said

7. would see

8. asked 

VI/

1. The topic which the passage is mainly concerned with is  the current  American family

2. The writer implies that there has always been a wide variety of family arrangements in America.

3. A one-person household is generally constituted by single people, usually women over sixty-five years of age.

4. The married couples whose children have grown or who have no children represent about 33,3 percent.

5. C (current: hiện tại = now)