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问题 选择题

下列物质反应后可生成较纯净的1，2-二溴乙烷的是[ ]

A．乙烯和溴化氢加成

B．乙烷和少量的溴蒸气光照

C．乙烯通入溴的四氯化碳溶液中

D．乙烷通入溴水中

答案

答案：C

单项选择题

猪肉绦虫病和牛肉绦虫病的主要传染源是( )。

A．人
B．带虫者
C．带虫动物
D．受感染的猪
E．受感染的牛
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选择题
While we ________ tennis yesterday, it ________ to rain.

A. played, was starting
B. played, started
C. were playing, was starting
D. were playing, started
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