单项选择题

How should you signal the crane operator to move slowly（）.

A.Use one hand to give any motion signal，and place the other hand motionless in front of the hand giving the motion signa
B.Extend arm with the thumb pointing up，and flex the fingers in and out for as long as the load movement is desired
C.First tap your elbow with one hand and then proceed to use regular signals
D.First tap the top of your head with your fist and then proceed to use regular signals

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单项选择题

How should you signal the crane operator to lower the boom and raise the load（）.

A.Extend arm and point finger in the direction to move the boom
B.Extend arm with thumb pointing downward and flex fingers in and out
C.With forearm vertical and forefinger pointing up，move hand in small horizontal circles
D.With arm extended downwards and forefinger pointing down，move hand in small horizontal circles

单项选择题

How should you signal the crane operator to hoist（）.

A.With forearm vertical and forefinger pointing up，move hand in small horizontal circles
B.With arm extended downwards and forefinger pointing down，move hand in small horizontal circles
C.Extend arm with fingers closed and thumb pointing upward
D.Place both fists in front of body with the thumbs pointing upward

单项选择题

Damage by（）shall not be considered as handling damage.

A.exposure to inclement weather conditions
B.carelessness
C.the use of improper gear
D.moisture caused by condensation