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Alaska is disappearing slowly but surely. Since the 1950s, it is estimated that as much as 15 percent of Alaska’s area has disappeared. But how can a whole state be disappearing? One reason for Alaska’s gradual disappearance is the melting its glaciers. According to one geologist at the US Geological Survey, about 98 percent of Alaska’s glaciers are either unmoving or diminishing. This diminishing seems mainly due to the increase in global temperatures. Since the 1960s, the average year-round temperature has increased by 5℉. Furthermore, the average winter temperature has increased by 8℉. Presently, an estimated 24 cubic miles of ice is disappearing from Alaskan glaciers every year. It may be even more in the near future, as some scientists predict that the average world temperature could go up 2.5 to 10℉by the year 2010. Another problem contributing to Alaska’s gradual disappearance is its permafrost. (4) Much of the land in Alaska was permanently frozen, or frozen for most of the year, thus maintaining its integrity. Now, the thawing permafrost is causing a number of problems on land. Roads and utility poles are collapsing. Also, the hard permafrost which originally prevented beaches from eroding during violent storms is now melting. Affected villages are forced to relocate. For villages on small low islands, one terrible storm could wipe out the entire community. The melting permafrost and increasing temperature are also having a negative impact on the forests of Alaska. As the permafrost under the forests melts, insects that normally don’t turn up until the warmer seasons are appearing sooner. The spruce-bark beetle, for example, is increasing in numbers as a result of global warming. It usually takes about two years for these beetles to grow and reproduce in a very cold weather. However, due to the increase in temperatures, spruce-bark beetles are damaging as many trees in one year as they previously damaged in two. At this rate, Alaska’s forest won’t survive the turn of the century. Some scientists believe that human activity is linked to a global increase in weather temperature. Whether the rising temperature are caused by human activity or natural changes, the fact remains that Alaska is warming. Some others argue that global warming may be a normal trend on the Earth’s temperature chart. (5) One theory argues that we are near the end of a so-called “Little Ice Age”, and the return of the glaciers is natural result of this cycle. Whether natural or produced by humans, there is little hope for the immediate future of glaciers as we know them. Horribly, this could be a preview of what will happen to the rest of the world in the next century. Questions 1-3 Answer the following questions briefly according to the passage. 1. What are disappearing in Alaska actually? 2. How much ice is melting each year according to the survey? 3. Why do insects damage more trees than before? Questions 4-5 Translate the underlined sentences in the passage into Chinese. 4. Much of the land in Alaska was permanently frozen, or frozen for most of the year, thus maintaining its integrity 5. One theory argues that we are near the end of a so-called “Little Ice Age”, and the return of the glaciers is natural result of this cycle. Whether natural or produced by humans, there is little hope for the immediate future of glaciers as we know them.
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参考答案:
举一反三
【判断题】上部向外突出,中间凹进的陡峭崖壁称为陡崖 。
A.
正确
B.
错误
【简答题】合成不饱和聚酯的主要原料是[填空(1)](或相应的酸酐)、饱和二元酸、二元醇和[填空(2)]。
【单选题】男式三件套西装的上衣都是单排扣,且有__________之分。
A.
一粒扣、两粒扣、三粒扣
B.
两粒扣、三粒扣、四粒扣
C.
一粒扣、三粒扣、五粒扣
D.
三粒扣、四粒扣、五粒扣
【判断题】在执行某个排序算法过程中,出现了排序码朝着最终排序序列位置相反方向移动,则该算法是不稳定的。( )
A.
正确
B.
错误
【判断题】不饱和聚酯一般由饱和及不饱和二元醇与饱和及不饱和二元酸(或酸酐)聚合而成
A.
正确
B.
错误
【单选题】饱和聚酯主要是以二元或多元醇和羧酸为原料,经过缩聚反应而成,目前使用最广泛的是( )。
A.
PET和PBT
B.
PA和PBT
C.
PET和PPT
D.
PET和PCL
【多选题】聚酯型人造石材是以不饱和聚酯树脂为胶结剂,主要品种有
A.
人造大理石
B.
人造花岗石
C.
人造玉石
D.
复合型人造石
【判断题】聚酯漆是不饱和聚酯树脂为主要成膜物质,由于不饱和聚酯树脂的干燥速度慢、 漆膜厚实丰满,有较高的光泽度和较好的保光性能,膜面硬度高,耐磨、耐热、耐寒、耐 溶剂和耐弱碱腐蚀的性能都好。 ( )
A.
正确
B.
错误
【多选题】合成不饱和聚酯的主要原料是 [填空(1)] (或相应的酸酐)、饱和二元酸、二元醇和 [填空(2)] 。
A.
不饱和二元酸
B.
乙烯基类交联单体
【简答题】饱和聚酯主要是以二元或多元醇和羧酸为原料,经过缩聚反应而成,目前使用最广泛的是 [填空(1)] 。A. PET和PBT
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