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單項(xiàng)選擇題

Pistons of marine medium speed diesel engines may be made of （） in order to keep the weight down for balancing purpose at high speed.

A.lead
B.forged steel
C.alloy steel
D.aluminum alloy

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單項(xiàng)選擇題

Pistons may be made in （） in order to keep the weight down for balancing purposes at high speed.

A.cast iron
B.forged steel
C.stainless steel
D.aluminum alloy

單項(xiàng)選擇題

Piston No2 of main engine has been removed, and it will be （） by noon tomorrow.

A.lifted
B.reassembled
C.dismounted
D.disassembled

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