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问题 选择题

用不同材料制成的体积相同的两种实心球a和b，如果天平的左盘放上2个a球，右盘放上3个b球，天平正好平衡，则下列判断正确的是：[ ]

A．ρa∶ρb＝3∶2

B．ρa∶ρb＝2∶3

C．ma∶mb＝1∶1

D．ma∶mb＝2∶3

答案

答案：A

听力题

根据句意及首字母或汉语提示，写出各句中所缺单词的正确形式。（每空一词，共10分）

小题1:As you go up a mountain, you have to overcome the earth’s g           which pulls you down.

小题2:The m             leaf has become the most important symbol of Canada since the national flag was introduced in 1965.

小题3:The little girl was t          at the thought of being left alone at home and cried.

小题4:He went to the United States in the 1980s and s                down there.

小题5:Don’t leave matches or cigarettes on the table w              reach of little children.

小题6:How quickly a fuel burns depends on how well it is mixed with              (氧气) or air.

小题7:The policemen were sent to find the black box because it showed why the plane had           

(坠毁).

小题8:The idea                 (存在) only in the minds of us young people today.

小题9:This problem is only                 (稍微) difficult so I can work out.

小题10:They claimed that when they were               (包围) by the gang they acted in self-defense.
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单项选择题

北京市海淀区公安分局就户籍管理事项向位于本行政辖区内的国家某部发文，应使用的文种是( )。

A．通知
B．请示
C．指示
D．函
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