单项选择题
What is the purpose of the equalizing beam aboard a crane vessel（）.
A.It allows for rotation of the hook in the single mode B.It is required to“twin-up”30-ton pedestal cranes C.It is used to pick up light loads D.It is used to rigidly connect two cranes
单项选择题 What is meant by the term“luffing the boom”of a crane（）．
单项选择题 What does “evel-luffing” accomplish during crane operations（）.
单项选择题 They（）loading at 1400 hours．
