进气管回火时PCV阀()。
A.全开
B.半开
C.关闭
D.开或关由当时发动机转速决定
参考答案:C
高空作业应()
A.穿防护服
B.穿防滑鞋
C.戴安全帽
D.系安全带
The director had her assistant _____some hot dogs for the meeting. [ ]
A. picked up
B. picks up
C. pick up
D. picking up