單項選擇題The signal man assisting a crane operator has his arm extended with his fingers closed and thumb pointing upward. This is the signal to（）.

A.raise the boom
B.raise the hook
C.raise the boom and hook
D.check the boom stop


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1.單項選擇題The rope which is the lightest is（）.

A.manila
B.nylon
C.polypropylene
D.dacron

3.單項選擇題The rolling hitch could be used to（）.

A.join two lines of different sizes
B.join two lines of equal sizes
C.add strength to a weak spot in a line
D.act as a stopper to transfer a line under strain

4.單項選擇題The purpose of a devil’s claw is to（）.

A.act as a chain stopper
B.prevent the windlass from engaging
C.prevent the chain from fouling on deck
D.control the wildcat

5.單項選擇題The only wire rope termination which may be made in the field is（）.

A.swaged socket
B.thimbled mechanical splice
C.hand splice
D.spelter poured and resin sockets