44. A. holding on B. giving in C. looking forward D.adding up
45. A. till B. as C. before D. once
46. A. defeat B. fight C. feel D. forget
47. A. clears B. escapes C. releases D. runs
48. A. Therefore B. Otherwise C. Moreover D. However
49. A. space B. reason C. chance D. time
50. A. other than B. more than C. rather than D. less than
51. A. adding to B. taking away C. subjecting to D.objecting to
52. A. gains B. takes C.keeps D. loses
53. A. Calm B. Relax C. Wait D. Stop
54. A. inform B. warn C. convince D. remind
55. A. already B. enough C. gone D. long
第三部分：阅读理解（共15小题；每小题2分，满分30分）
请认真阅读下列短文, 从短文后各题所给的A、B、C、D 四个选项中, 选出最佳选项, 并在答题纸上将该项涂黑。
A
The tree people in the Lord of the Rings—the Ents—can get around by walking. But for real trees, well, it's harder to uproot. "Because it's a sessile organism, literally, rooted into the ground, it is unable to leave and go elsewhere." Mario Pesendorfer, a behavioral ecologist at the Cornell Lab of Ornithology. "When a tree first starts growing in a certain area, it's likely that the climatic envelope, so the temperature, humidity, soil composition and so on suits it, because it would otherwise be unable to grow from a seedling. But as it ages, these conditions may change and the area around it may no longer be suitable for its offspring."
And if that happens? Walnuts, hazelnuts, chestnuts, oaks, pines—many rely exclusively on so-called "scatter-hoarders," like birds, to move their hefty seeds to new locales. "Many members of the family Corvidae—the crows, jays and magpies—are scatter-hoarders, meaning they like to store food for the winter, which they then subsequently retrieve."
Or not. And when they do forget something, a seedling has a chance to grow, sometimes a good distance away. "The Clark's nutcracker, which is found in alpine regions of western North America, is definitely the rock star among the scatter-hoarding corvids. They hide up to 100,000 seeds per year, up to 30 kilometers away from the seed source, and have a very close symbiotic relationship with several pine species, most notably the whitebark pine.‖
Pesendorfer and his colleagues catalogue the seed-scattering activities of the Clark's nutcracker and its cousins in a new review paper, in the journal The Condor: Ornithological Applications. They also write that, as trees outgrow their ideal habitats in the face of climate change, or battle new insects and disease, these flying ecosystem engineers could be a big help replanting trees. It's a solution, Pesendorfer says, that's good for us—getting birds to do the work is cheap and effective— and it could give vulnerable oaks and pines the option to truly "make like a tree and leave."
56. According to the article, what makes birds help trees move from one place to another? ________.
A. They want to make the environment better for survival
B. They want to change the trees into another kind
C. They want to store the nuts for winter survival
D. They are forced to help trees to survive
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