单项选择题
A.Lightning
B.High winds
C.Fire aboard
D.All of the above
单项选择题 During which condition should the operator of a pedestal crane shutdown operations?（）
单项选择题 During which condition should the operator of a pedestal crane shutdown operations?（）
单项选择题 During transfer operations，a quantity of propylamine spills on deck. According to the Chemical Data Guide，the correct procedure would be to（）.