搜题请搜索小程序“爱下问搜题”
问题
选择题
某有机物在氧气中完全燃烧，生成CO
2
和H
2
O的质量比为22：9，则该有机物可能是（ ）
A．C
2
H
4
B．C
6
H
6
C．CH
4
D．C
2
H
5
OH
答案
答案：
A
选择题
I saw a woman running towards me in the dark. Before I could recognize who she was, she had run back in the direction-______ she had come.
A. of which
B. by which
C. in which
D. from which
查看答案
问答题 简答题
凝结水泵在启动时为什么要关闭出口门？
查看答案
