压力容器上的开孔补强圈应当至少设置（）个泄漏信号指示孔。
A.一
B.二
C.三
D.不需要设置
参考答案：A
在分馏塔的操作中，气相负荷过大会导致（）。
A、漏液
B、降液管超负荷
C、雾沫夹带
D、鼓泡
It is politely requested by the hotel management that radios __________ after 11 o'clock at night.[ ]
A. were not played
B. not be played
C. not to play
D. did not play
