[外语类试卷]大学英语四级模拟试卷357及答案与解析.doc
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1、大学英语四级模拟试卷 357及答案与解析 一、 Part I Writing (30 minutes) 1 For this part, you are allowed thirty minutes to write a composition on the topic Changing Criteria for Judging a Good Student. You should write at least 120 words and you should base your composition on the outline (given in Chinese) below. Chan
2、ging Criteria for Judging a Good Student 1以往判断一个好学生的标准; 2现今判断一个好学生的标准发生了哪些变化; 3这些变化是符合社会要求的。 二、 Part II Reading Comprehension (Skimming and Scanning) (15 minutes) Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions attached to the passage. For q
3、uestions 1-7, mark: Y (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. 1 Degraded Land in South China Damaging agricultural and
4、 forestry practices over the past years have degraded half of the land in China bounded by the Tropic of Cancer and the South China Sea, dramatically reducing its biological productivity and environmental services. The damage to South Chinas hilly tropical/subtropical(亚热带的 ) forests probably began i
5、n the Sung Dynasty as population expanded to the south. The settlers most likely used cutting and bum techniques to clear land for fanning. Forest cover provided building materials and firewood to the settlers, but also served as a habitat(栖息地 ) for tigers, leopards, wild pigs, and deer. Population
6、growth put severe pressure on the land. Eventually, erosion (腐蚀 ) washed away much of the top soil and much of the degraded land was abandoned. Today, only about one square kilometer of the original tropical evergreen broad-leaved forest remains. Impacts The most direct impact of this disastrous los
7、s of productive soil is reduced agricultural production. Farmers trying to produce crops under these conditions face great difficulties even when using commercial fertilizers(化肥 ). The soil is poor at holding the plant nutrients(营养 ) contained in commercial fertilizers. The problem is deteriorated b
8、y the fact that fertilizer runs off the land quickly during heavy rains. China cannot afford to abandon potentially productive land, let alone lose more to erosion. It is already losing enormous amounts of land to new towns and other non-agricultural uses. Per capita amble land (人均可耕种土地 ) in China n
9、ow is about 0.1 hectare, only 47 percent of the world average. But China estimates that it lost about 50,000 square kilometers of its amble land from 1986 to 1995, the equivalent of the total agricultural land area of Japan. Food production is not the only problem. The loss of much of China s forest
10、 cover today has made wood products China s leading import costing the country $ 2 to $ 5 billion annually. Economic losses also result from waterlogged (水涝的 ) fields and coastal sand storms that result directly from the soil erosion. Some 710 million tons of sediment(沉淀物 )were carried through the T
11、hree Gorges(三峡 ) part of the Yangtze in 1998-a 33 percent increase over the loads measured before 1990. In parts of Guangdong Province, sediment-choked streams and rivers have caused the water table to rise and have waterlogged nearby farm fields. Since the waterlogged land is useless for convention
12、al fanning, the Chinese introduced the “dam-pond system“. Ponds are dug and used for raising fish and vegetables are grown on the tops of the dam surrounding the ponds. This system may have to be ridiculously stopped if erosion is controlled. Once controlled, the streams and rivers will cut deeper c
13、hannels, thus lowering the water level in the fishponds. In the few areas where reforestation (重新造林 ) of eroded hills has reduced erosion and sediments in the rivers, the river has begun to cut through years of deposited sediment to return to its original bed. This lower water table(地下水位 ) reduces w
14、ater logging of nearby land and the fishponds begin to dry up. In some places, pumps had to be installed to draw water from the streams and rivers to keep the water level in the fishponds stable. Sandstorms are another effect of the heavy sediment load created when granite (花岗岩 )weathers (风化 )in the
15、 wet tropics. Coarse quartz(粗的石英 ) sands move from the weathered hills to lower elevations during heavy rains, filling valleys and covering agricultural fields. Fine-grained quartz sands, however, are carried further downstream and deposited near river mouths. Strong sea winds and typhoons regularly
16、 blow the sand inland, burying agricultural fields and human settlements. To reduce the movement of sand by wind action, the Chinese built windbreaks(防风林 )along much of the sandcovered coastal belt. Salt-tolerant (耐盐的 )trees, satisfactory for such coastal windbreaks, were planted near the shore. Bec
17、ause these trees are exposed to local people looking for firewood, the government normally prohibits tree cutting but allows them to dump rubbish beneath the trees for cookingfuel. Loss of covering plants and soil means that heavy tropical rains flow rapidly into streams and rivers, causing disastro
18、us flooding. The damaging floods and landslides(山崩 ) in lands adjacent to the Yangtze and Yellow Rivers in 1998 were a direct consequence of the loss of forests and other plant in the rivers headwaters(上游 ) and over-fanning. These floods killed many and destroyed homes, roads, bridges, and other con
19、struction. In Jiangxi province alone, the government had to resettle 600 thousand people from along the flooded Yangtze River. Some Solutions Scientists in research institutions throughout South China have worked for decades to develop and test methods for restoring degraded lands to productive land
20、s using a combination of agriculture and forestry methods called agroforestry. Since funds are scarce and the problem is large, any practical solution must be able to begin creating an income for .the regions farmers within a few years. This has led to some creative and promising strategies for rest
21、oring some of the most severely weathered regions. Techniques, of course, must be adapted to fit each cultural and environmental region. Many of the most effective approaches rely on knowledge gathered from traditional systems practiced by ethnic minority groups in the affected regions. The process
22、starts with a fast growing ground cover that can shade the soil and make it possible for other seeds to grow. Care must be taken to ensure that this new cover survives the dry season when grass fires present serious hazards. Fire prevention can be extremely difficult in areas where open flames are u
23、sed for cooking and for religious practices. These early plantings are typically made at the beginning of the rainy season when the ground is comparatively cool. he wet season gives the plants an opportunity to establish themselves and provide leaf cover for shade. It is essential to pick pioneer sp
24、ecies that can provide some income for farmers in the first year income that will sustain the farmers until other crops establish themselves. Part of the art is finding a combination of crops that can occupy the same site. Above ground, this means matching demands for sunlight and shade. Rubber tree
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