31.Weather forecasting was of vital (important) in the seafaring (and agricultural) lives (led by) the seventeenth-century European colonists (in what) is now the United States.
答案:A。important--------->importance
32.One (common) herb of the mint family is thyme, the (dried) leaves and flowering tops of which (is) used (to flavor) many different food.
答案:C。is--------->are
33. Birds usually (have very) well-developed sense of (sight), and the optic lobes of (their brains) are (correspondingly) large.
答案:A。“have very--------->have a very”,很多人对这道题费解,以为错在very上了,其实very没错,而是应该再前面加一个“a”。“sense”是感觉的意思,一般用“a sense of”。比如“a sense of fatigue and hunger,a keen sense of humor”。
34. Peter Cooper launched a number of (successful) commercial (enterprise), including the Canton Iron Works in Baltimore, (which produced) the first (commercially operated) North American steam locomotive.
答案:B。enterprise--------->enterprises
35.Fainting (is caused) by stoppage of the blood supply to brain, due to (temporary) heart (fail) from shock, (weakness), or exhaustion.
答案:C。fail--------->failure
36.The Fundamental physical (principle) of photography is that (light falling) on the grains (of certain) insoluble silver salts produces small, (invisibly) changes in the grains.
答案:D。invisibly--------->invisible
37. The oxygen of the atmosphere, (so) essential to (many of) forms of life, (represents) the accumulated product of over 3,500,000,000 years of photosynthesis (by) green plants.
答案:B。many of--------->many
38. Most of the world’s energy ----(including) wind (and) water power and (all) fossil fuels ---(come) indirectly from the Sun.
答案:D。come--------->comes
39.(The wolf) was once the (most widely) distributed (kind of) mammal (on) the world.
答案:D。on--------->in
40. Instruments that (measure) the passage (of time) have been in (exist) for (about) 4,000 years.
答案:C。exist--------->existance