烘衬里时，用来控制反应压力的是（）。
A、沉降器顶放空自控阀
B、分馏塔顶蝶（闸）阀
C、气压机入口放火炬阀
D、气压机出口放火炬阀
参考答案：A
The yellow shirt is _____ sale _____ 24. [ ]
A. at; at
B. on, for
C. at; for
D. on; of
This new-type machine____________ little room.
A．takes up
B．is taken up
C．has been taken up
D．is taking up
