什么叫做燃气的比重？
参考答案：
燃气的比重是指燃气的重度与空气的重度之比，他是一个无因次量。
选择填空。
— Do you want to work ______ people from all the places?
— Yes. I like ______ people in many kinds of languages. [ ]
A．with; talking
B．and; talking to
C．with; talking to
