How should you signal the crane operator to stop in an emergency?______.
A.Extend arm with the palm down and hold this position rigidly
B.Placed clasped hands in front of your body
C.Extend arm and move hand rapidly right and left with the palm down
D.Place both fists in front of your body with thumbs pointing pointing outward
正确答案：C
你应怎样指挥起货机手急停？展开臂膀并快速移动手掌向下的左右手
