调节阀的特点是什么？
参考答案：调节阀是用来调节介质流量的装置，其流量大小随调节阀开度大小而增加或减少。
---- What did you think of her speech?
--- She _______ for one hour but didn’t _______ much.
A．spoke,speak
B．spoke, say
C．said, speak
D．said, say
交、直流电源电缆必须（）布放电源电缆和信号线缆应分离布放。
