21.

42. Which of the following processes will increase salinity of ocean waters?

47. What does Grace Kao say about interracial lodging?

19. So large is the Pacific, _____ 30% of the earth’s surface, that the energy generated by its warming is enough to touch off a series of weather changes.

31.张老师认为教育就是为了要让学生学习知识，把握学习内容。张老师遵循的理论是（ ）。

45. What does Sam Boakye’s remark mean?

49. Which of the following is true about the research under discussion?

40.

4. Race remains a prominent and ______ issue in the United States, which has struggled to overcome a legacy of slavery and discrimination.

1. ______ increase in the oil price have prompted anxiety among the car owners.

16. I see no reason why they shouldn’t go on playing for another four or five years ______ they are fit enough. 

39.