空调工况的蒸发温度是（）。
A、-50C
B、+50C
C、+7.20C
D、+100C
参考答案：B
----The teacher didn’t realize you had cheated in the exam.
----Well, _____!
A．what a relief
B．with great pleasure
C．no chance
D．that’s fine with me
煤的磨损指数
