空气压缩机每作业(),应将液气分离器、中间冷却器、后冷却器内的油水排放一次。贮气罐内的油水每班应排放1次~2次。
A.1h
B.2h
C.3h
D.4h
参考答案:B
He went down into the cold water and after ________seemed a long time, he came out.
A.that
B.what
C.which
D.it
“青年志愿者行动”是()年在我国第一次走向了社会。