经测定由C3H7OH和C6H12组成的混合物中氧的质量分数为8%，则此混_爱下问搜题

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问题不定项选择题

经测定由C₃H₇OH和C₆H₁₂组成的混合物中氧的质量分数为8%，则此混合物中氢的质量分数是[ ]

A．78%

B．22%

C．14%

D．13%

答案

答案：C

选择题

First impressions are the most lasting. After all, you never get _____ second chance to make _____ first

impression. [ ]

A. a; the

B. the; the

C. a; a

D. the ; a

名词解释

单亲遗传