单项选择题
A.gas oil B.diesel oil C.chemical compound D.Freon-12
In the cargo winch, spur reduction gearing transfers th...
单项选择题In the cargo winch, spur reduction gearing transfers the motor drive to （）.
A.the toping light B.the board brake C.the fail-safe D.the barrel shaft
For occasional heavy loads, two cranes can be arranged ...
单项选择题For occasional heavy loads, two cranes can be arranged to work together. The operating （） for deck crane motors may be hydraulic electric.
A.principle B.medium C.instruction D.voltage
In a general cargo crane, three principal movements are...
单项选择题In a general cargo crane, three principal movements are （）； （）； （）.
A.hoisting；luffing；slewing B.lifting；raising；lowering C.rotating；raising；handling D.hosting；lowering；moving
