空分设备的吸气口应超出制氧(站)屋檐1m以上且离地面垂直高度必须大于( )m。
A．5
B．8
C．10
D．12
参考答案：C
It was very hot yesterday, but it is __ today. [ ]
A. even hotter
B. more hotter
C. much more hot
高炉煤气加热时，主管压力低于（）Pa时，应停止加热。
A.1000
B.500
C.300
