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1、12月大学英语四级考试模拟试题及答案(1)12月英语四级考试模拟试题及答案(1)Part I Writing (30 minutes)Directions: For this part, you are allowed 30 minutes to write a composition on the topic: To Be a Small Fish in a Big Pond or a Big Fish in a Small Pond? You should write at least 120 words following the outline given below in Chine
2、se:1. 在大企业工作的特点2. 在小企业工作的特点3. 我的选择To Be a Small Fish in a Big Pond or a Big Fish in a Small Pond?Part II Reading Comprehension (Skimming and Scanning) (15minutes)Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions on Answer Sheet 1. For question
3、s 1-7, markY (for YES) if the statement agrees with the information given in the passage;N (for NO) if the statement contradicts the information given in the passage;NG (for NOT GIVEN) if the information is not given in the passage.For questions 8-10, complete the sentences with the information give
4、n in the passage.To Save Trees, Fighting One Alien Insect with OthersRusty rhea sighs wistfully as he talks about the beauty and peace of standing amid a grove (小树林) of deep green hemlocks in Appalachia, some of them up to 160 feet (50 meters) tall and more than 500 years old.This is a very special
5、tree, said Rhea, an entomologist for the U.S. Forest Services Forest Health Protection program in Asheville, North Carolina, I was brought up here, and I dont want to see another species go by the wayside.The evergreen trees, a hallmark of southern Appalachias national parks, are under attack by an
6、invasive inse4ct barely visible to the eye but potent enough to fell the giants of the eastern United States old-growth forests.Already the tiny bug from Japan, known as the hemlock woolly adelgid (HWA), has killed upward of 95 percent of the hemlocks in Virginias Shenandoah National Park. Now they
7、are making their way through the half-million-plus-acre (200,000-plus-hectare) Great Smoky Mountains National Park in North Carolina and Tennessee.The hemlocks shade streams, keeping water temperatures just right for brook trout (鲑鱼) and other fish. They also house birds such as the black-throated g
8、reen warbler, solitary vireo, and northern goshawk, all three of which mainly shelter in stands of hemlock trees.Because of the insects broad impact on the entire ecosystem of southern Appalachia, HWA stands to cause wider damage than the American chestnut blight (枯萎病)of the early 1900s. That fungus
9、 from Europe killed off the once dominant chestnut trees from the northeast United States to the southern Appalachian Mountains.In addition, a species related to HWA, the balsam woolly adelgid, has already killed about 90 percent of the mature Fraser fir trees in the Smokies.Acting QuicklyHWA arrive
10、d in the U.S. Pacific Northwest via nursery plants from Japan in 1924. By 1951 the tiny invader had been found in Virginia. Since then the insect has spread to more than 15 U.S. states.The key to killing the HWA is to catch it early and act quickly. Its already well established in the Great Smoky Mo
11、untains, where Rhea and others are trying to stem the spread of the bugs.HWA multiply quickly: All of the insects are females that reproduce asexually (无性地), laying several hundred eggs a year. When they get to the nymph, or crawler, stage, they are dormant from about June until October, after which
12、 they emerge and establish themselves on trees.Winds and birds and other animals spread the crawlers through the forest.HWA crawlers feed on the new growth of hemlocks by piercing the twigs that hold the branches, sucking the sap, and injecting toxic saliva. The needles turn from a deep green to a g
13、rayish green and eventually die, depriving the tree of nutrition from photosynthesis.An infected tree usually dies within five years of initial attack. Infection is signaled by either a white, cottonlike material that appears along a trees twigs or by the baldness of a trees upper branches.Plans of
14、AttackIn the Pacific Northwest the hemlocks seem to be tolerant of the creatures feeding, and in the cold northeast, winters seem to keep them at bay. But in the warm southeast, with weather approximating that of the insects native Asian homes, they thrive.Chemical sprays-such as insecticidal soaps
15、and horticultural oils as well as trunk or soil injections-have helped to kill some of the HWA infestations.But spraying must be repeated every six months, and injections are expensive and last only two years at most. These methods cant be used conveniently or safely in remote areas or near the stre
16、ams where hemlocks grow thickly.Long term, the best way to control the pests appears to be releasing other insects that feed exclusively on HWA. Scientists have studied HWA in Japan and China and identified three such species. One of them, the Sasajiscymnus tsugae (St) beetle, was released in areas of Great Smoky Mountains National Park in .Studying what controls a species in its native habitat-including climat
