单项选择题
A.Keep a load on the hoist until all personnel are finished working
B.Set the load on a movable dolly when transportation may be needed
C.Have one man keep a hand on the load to steady it
D.Insure that the lifting gear capacity is not exceeded
单项选择题 Which of the actions listed and instituted on your part will have the greatest lasting effect on the crew with respect to safety?（）
单项选择题 Which of the listed conditions can be considered as the single greatest cause of accidents?（）
单项选择题 Which of the following must be eliminated to prevent accidents?（）