单项选择题
Pedestal cranes have limit switches to restrict movement of which function（s）（）.
A.Hoist upper & lower limits B.Luff travel limits C.Rider block hoist upper & lower limits D.All of the above
单项选择题 On no account（）to be exceeded.
单项选择题 Official draft measurements should be（）by authorized persons，agreed by both parties involved.
单项选择题 Most pedestal crane power is provided by（）.
