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。
—Are you going to but a new camera?
—Yes. But there are so many cameras that I can’t decide______________.
A. how to use B. where to sell C. which to buy
下列各穴中，属足太阴脾经的是
A．大横B．章门C．期门D．粱门E．带脉
