水蒸气的饱和状态。
参考答案：
是汽化和液化达到动态平衡共存的状态。
如图所示的四种情景中，属于光的反射的是（ ）
A．
B．
C．
D．
—Do you know ______ the MP4 yesterday?
—Sorry, I've no idea about it. [ ]
A. how much did he pay for
B. how much he paid for
C. he paid for how much
D. he paid how much for
