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單項(xiàng)選擇題

Keep compartment （） as the gas given off can be dangerous.

A.well ventilated
B.well clean
C.in good order
D.more room

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單項(xiàng)選擇題

More than one stage of evaporation can take place by admitting the sea water into chambers with progressively （） pressure in the flash evaporator.

A.lower
B.higher
C.the lower
D.the higher

單項(xiàng)選擇題

In the process of （）, liquid changes into gas.

A.evaporation
B.frosting
C.condensing
D.compressing

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