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單項選擇題

The switchboards for a-csystems differ from the d-cswitch gear in that the open type panels are generally（） and the dead-front switch gear is the common rule.

A.permissibly
B.permissible
C.no permissible
D.not permissible

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單項選擇題

Electrical supply is always needed even if only for lighting so after a ship goes into service it is extremely rare for the main bus-bars to be dead, it therefore follows that the bus-bars are continuously alive（） the life of the ship.

A.along
B.will
C.throughout
D.for

單項選擇題

The current flowing first in one direction and then in another is called（） current.

A.an alternating
B.a rush
C.a direct
D.an exciting

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