无码高清视频|成人自拍视频|欧美成人午夜无码A片秀色直播|草美女视频网站|美女被操网站在线观看

單項選擇題

Which of the listed items should be secured before performing any maintenance on a solenoid operated air start valve?()

A.Electric power and starting air
B.Lube oil standby pump and control air
C.Hydraulic switch and engage jacking gear
D.Motor drain and pneumatic control system power

微信掃碼免費搜題