问题
选择题
You must come with us to the police __________ Our head is waiting for you.
A．headquarter
B．headline
C．headmaster
D．headache
答案
答案：A
搜题请搜索小程序“爱下问搜题”
You must come with us to the police __________ Our head is waiting for you.
A．headquarter
B．headline
C．headmaster
D．headache
答案：A
N2O4，所得混合气体中NO2的体积百分含量为40%，此时，混合气体的平均分子量为[ ]