输送介质为轻油的离心泵,检修前可不进行()操作。
A.切断电源
B.吹扫
C.泄压
D.关闭进出口阀
参考答案:B
Which of the following is not a cause for Air France's earnings to rise before interest and tax
A.The drop in fuel cost.
B.The rise in cargo traffic.
C.The rise in passenger traffic.
D.Its partnership with Alitalia SpA.
竞争释放