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單項選擇題

When the union purchase derrick is operated, one derrick is positioned over the quayside and the other almost vertically over the （）.

A.dock
B.hold
C.pedestal
D.machinery space

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單項選擇題

In a general cargo crane, （） is fitted to lift the cargo load.

A.the slewing motor
B.the luffing motor
C.the hoisting motor
D.none of the above

單項選擇題

The crane is usually mounted on a pedestal to offer adequate （） to the operator.

A.time
B.space
C.length
D.visibility

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