16. Sea turtles date back 100 million year and are the only ancient sea reptiles to survive the present Day.
17. At a first, the scientific method may appear to be a narrow and restrictive way of gaining understanding. 答案：A
18. Since prehistoric times, artists have portrayed subjects that representative their culture. 答案：D
19. How many people realize that agriculture is a source of raw materials for clothing and to shelter? 答案：D
20. Mammals lose body heat to them environment in cold weather more quickly than in hot weather.
21. Mahogany is often considered the finest cabinet wood because they has most of the qualities desired for furniture making.
22. The situation comedy has proved to a remarkably durable commercial television format. 答案：B
23. Calcium, the most abundantly mineral in the body works with phosphorus in maintaining bones and teeth. 答案：A
24. Soil science begun with the formulation of the theory of humus in1808. 答案：A
25. Scholars tend to cite 1831 as the started of the United States abolitionist movement. 答案：C 测试点：词性。
26. Mary McDowell shared Jane Addam’s interest in social work also was a loyal supprter of the League of Nations.
27. In adolescence, a young person may experience some stress emotional due to conflicting and confusing social demands.
28. Situated in the heart of a grain-farming and livestock-raising region, Abilene, Kansas, is a prosperous trading and distribute center.
29. A hologram is a pattern usually made on film in that can create a three-dimensional image of a scene.
30. The general sales tax has been a major source of income for state governments, much of which derive more than half of their budgets from it.
31. Principal known for his dictionary, Noah Webster was also the first epidimiologist in the United States.
32. Liquid lubricants contrast widely in weighing, thickness, and boiling point. 答案：C
33. Interest with major social events led to a period of growth in journalism after 1945. 答案：A
34. Saint Elmo’s fire is a luminous blue discharge of electricity sometimes seen when a thunderstorm.
35. Almanacs in simple form have been known from the invention of writing. 答案：B 测试点：since和from的用法．
分析：since和from常被相互错用．由have been known知道此句是现在完成时态，应想到时间状语该用since，不能用from．
36. If laid out in straight line, the human digestive tract would measure approximately thirty foot in length. 答案：D
37. The relationship of Latin American music to Black music in the United States is clearly evident in the unaccented beats that are common to either. 答案：D
分析：“两者的共同特点”应是common to both，不用either．(B)clearly evident正确并非同意重复．
38. Today it is generally recognized as the primary function of the Federal Reserve System is to foster the flow of credit and money that will eventually facilitate a balance in
分析：看到it is…的句式，应立即注意其是否用了“形式主语+that从句(或十不定式)”结构。这样，才不会被recognized as所迷惑。as应为that，引导真正的主语。
39. Pure flint is too hard and even-grained that it chips in smooth curved flakes. 答案：B
40. The typical Georgian-style house is rectangular in shape, at less two stories high, and designed around a central stairway.