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【简答题】
Directions: This exercise practises skimming and scanning-- that means reading very fast to find only the main ideas of a text. You will have only five minutes to read the text and identify the main ideas. Choose the correct answer for each question. Passage 1 Every second, 1 hectare of the world's rainforest is destroyed. That's equivalent to two football fields. An area the size of New York City is lost every day. In a year, that adds up to 31 million hectares -- more than the land area of Poland . This alarming rate of destruction has serious consequences for the environment; scientists estimate, for example, that 137 species of plant, insect or animal become extinct every day due to logging. In British Columbia, where, since 1990, thirteen rainforest valleys have been clearcut, 142 species of salmon have already become extinct, and the habitats of grizzly bears, wolves and many other creatures are threatened. Logging, however, provides jobs, profits, taxes for the government and cheap products of all kinds for consumers, so the government is reluctant to restrict or control it.
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举一反三
【单选题】不宜磨削加工的材料是
A.
有色金属
B.
淬火钢
C.
铸铁
D.
中碳钢
【多选题】下列属于中国古代的物质观的是
A.
五行说
B.
阴阳说
C.
元气说
D.
四根说
【判断题】硬度很低而韧度较大的金属材料不宜采用磨削加工。
A.
正确
B.
错误
【单选题】在OSI参考模型中,服务正确理解为( )
A.
各层向下层提供操作
B.
各层间对等实体间通信的功能实现
C.
各层向上层提供的一组功能
D.
和协议的含义一样
【判断题】磨削加工不适宜加工塑性较大的有色金属材料。
A.
正确
B.
错误
【多选题】大量生产中平面加工常采用的两种方法是______。
A.
刨削
B.
铣削
C.
刮削
D.
镗削
E.
平面磨削
F.
组合磨床磨削
【简答题】表面质量要求较高的各种平面的 加工和 , 常采用 方法。平面磨削常用的机床是 , 砂轮的工作表面可以是 表面 , 也可以是 。
【单选题】不宜用磨削方法加工的材料是( )
A.
铸铁
B.
合金钢
C.
碳素钢
D.
有色金属
【单选题】炭疽芽胞杆菌形成芽胞的最适温度为
A.
10℃~15℃
B.
15℃~20℃
C.
20℃~25℃
D.
25℃~30℃
E.
30℃~37℃
【判断题】铣平面、刨平面是常用的叉架类零件平面的粗加工方法。
A.
正确
B.
错误
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