紧急停离心式压缩机,应执行的步骤有()。
A、关闭富气出入口阀
B、全开汽轮机机体及主汽门后各排凝阀,加强脱水
C、分馏塔顶气体放火炬
D、按规定盘车
参考答案:A, B, C, D
30. He is badly down these days. This sentence probably means _____.
A.He is seriously ill these days.
B.He is in low spirit these days.
C.He fell down and was seriously hurt.
D.He didn’t study hard these days.
有机固体废物厌氧发酵是指固体废物中的有机成分在厌氧条件下,利用厌氧微生物()的功能。转化为无机物质和自身的细胞物质,从而达到消除污染、净化环境的目的。
A.呼吸
B.光合作用
C.新陈代谢
D.生物合成