单项选择题
A.The bottom block touches the top block B.The line has jumped the sheaves C.There are turns in the fall D.You have two blocks
The use of（）between bags may lead to chafe and tearing ...
单项选择题The use of（）between bags may lead to chafe and tearing of the bags.
A.strips of burlap B.heavy paper C.dunnage boards D.strips of rope yarn
The tackle that raises and lowers the boom is（）.A.the c...
单项选择题The tackle that raises and lowers the boom is（）.
A.the cargo fall B.The cargo hoisting wire rope C.the topping lift D.the cargo whip
The strongest of the natural fiber ropes is（）.A.NylonB....
单项选择题The strongest of the natural fiber ropes is（）.
A.Nylon B.Dacron C.Manila D.Sisal
