How should you signal the crane operator to stop?______.
A.Place both fists in front of your body with thumbs pointing pointing outward
B.With both arms extended out and palms down, move arms back and forth
C.Extend arm with the palm down and hold this position rigidly
D.Clasp hands in front of your body
正确答案：C
你应怎样指挥起货机手停止？展开臂膀手掌向下并坚挺的地保持这个位置
