2016年12月大学英语六级考试真题与答案下载(第二套)

　　Section A

　　In this section, there is a passage with ten blanks. You are required to select one word for each blank from a list of choices given in a word bank following the passage. Read the passage through carefully before making your choices. Each choice in the bank is identified by a letter. Please mark the corresponding letter for each item on Answer Sheet 2 with a single line through the centre. You may not use any of the words in the bank more than once.

　　Questions 26 to 35 are based on the following passage.

　　The tree people in the Lord of the Rings--the Ents--can get around by walking. But for real trees, it's harder to uproot. Because they're literally rooted into the ground, they are unable to leave and go 26 .

　　When a tree first starts growing in a certain area, it's likely that the 27 envelope—the temperature, humidity, rainfall patterns and so on--suits it. Otherwise, it would be unable to grow from a seedling. But as it 28, these conditions may change and the area around it may no longer be suitable for its 29 .

　　When that happens, many trees like walnuts, oaks and pines, rely 30 on so-called "scatter hoarders," such as birds, to move their seeds to new localities. Many birds like to store food for the winter, which they 31 retrieve.when the birds forget to retrieve their food--and they do sometimes--a seedling has a chance to grow. The bird Clark's nutcracker, for example, hides up to 100,000 seeds per year, up to 30 kilometers away from the seed source, and has a very close symbiotic (共生的) relationship with several pine species, most 32 the whitebark pine.

　　As trees outgrow their ideal 33 in the face of climate change, these flying ecosystem engineers could be a big help in 34 trees. It's a solution for us--getting birds to do the work is cheap and effective--and it could give 35 oaks and pines the option to truly "make like a tree and leave. "

　　A. ages

　　B. breathing

　　C. climatic

　　D. elsewhere

　　E. exclusively

　　F. forever

　　G. fruitful

　　H. habitats

　　I. legacy

　　J. notably

　　K. offspring

　　L. replanting

　　M. subsequently

　　N. vulnerable

　　O. withdraws