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问题 选择题

现有六种物质，它们按下列顺序排列①CO ②H2O ③NH3④X ⑤C2H4⑥P2O5根据它们的组成和排列规律，推断X可能是（　　）

A．CH3OH

B．CH4

C．Fe2O3

D．SO3

答案

根据它们的组成和排列规律发现，都是原子构成分子，分子构成物质，但原子个数不同，①中2个原子，②中3个原子③中4个原子，④是未知的，⑤中6个原子，⑥中7个原子，则按照原子个数由小到大的顺序，④中应有5个原子．

A中有6个原子，故A错误．

B中有5个原子，故B正确．

C中有5个原子，但氧化铁不是由分子构成的，故C错误．

D中有4个原子，故D错误．

故选B．

填空题

During the 1980s, unemployment (失业人数) and underemployment (不充分就业) in some countries was so high as 90 per cent. Some countries did not 【B1】 enough food; basic needs in housing and clothing were not 【B2】 . Many of these countries looked 【B3】 the industrial processes of the developed nations for solution. 【B4】 , problems cannot always be solved by 【B5】 the industrialized nations. Industry in the developed nations is highly automated and very 【B6】 . It provides fewer jobs than labor-intensive industrial 【B7】 , and highly skilled workers are needed to 【B8】 and repair the equipment. These workers must be trained, 【B9】 many nations do not have the necessary training institutions. Thus, the 【B10】 of importing industry becomes higher. Students must be sent abroad to receive vocational and 【B11】 training. 【B12】 , just to begin training, the students must 【B13】 learn English, French, Germans, or Japanese. The students then spend many years abroad, and 【B14】 do not return home. All nations agree that science and technology should be shared. The point is: countries 【B15】 the industrial processes of the developed nations need to look carefully 【B16】 the costs, be cause ninny of these costs are 【B17】 Students from these nations should 【B18】 the problems of the industrialized countries closely. 【B19】 care, they will take home not the problems of science and technology, 【B20】 the benefits.

A．Through

B．With

C．In

D．Under
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单项选择题

核爆炸和地震灾害之类的仿真模拟，其应用领域是( )。

A．计算机辅助
B．科学计算
C．数据处理
D．实时控制
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