单项选择题
The boom indicator tells the operator at what angle the boom is compared to the（）.
A.horizontal position of the boom B.vertical position of the boom C.horizontal position of the load being lifted D.vertical position of the load being lifted
单项选择题 The boom indicator on a crane will indicate the（）.
单项选择题 Stop（）the derrick at once，the gooseneck is bent.
单项选择题 On no account（）to be exceeded.
