新换锅炉玻璃板式水位计后，应_________暖管。A.先稍开通汽阀B.先稍开通水阀C.先稍开冲洗阀D.同时

A vacuum is initially created in a flash type distilling plant by _____.

A.the flashing of the feed water

B.the condensation of the saltwater feed

C.air ejectors, eductors, or a separate vacuum pump

D.condensation of the distillate

制冷系统中热力膨胀阀温包从管路上脱开则阀_________。

A.开大

B.全关

C.开度视蒸发压力而定

D.开度变小

A semiconductor is a material with a _____.

A.conductivity higher than a normal conductor

B.conductivity higher than a normal insulator

C.high conductivity at low temperatures

D.low conductivity at high temperatures

锅炉水加了_________水处理药会产生泥渣沉淀。

A.氢氧化钠

B.磷酸二钠

C.磷酸三钠

D.B和C

Which of the petroleum products listed has the lowest flash point?

A.Hydraulic oil

B.Lubricating oil

C.Diesel oil

D.Refrigeration oil

irculation of water.

A.fire-tubes

B.furnaces

C.down-comers

D.soot-blowers

Who will mainly handle the negotiation during store and spare parts transaction?

A.Chief engineer

B.Second engineer

C.Master

D.Chief engineer

s of the UMS ship bridge control.

A.starting and direction changing trial

B.cancelling accelerating function trial

C.lowest stable speed trial

D.continuous running trial

the _____.

A.compressor

B.cooling coils

C.condenser

D.receiver

离心式分油机的出水口直径（）。

A.大于出油和进油口直径

B.大于进油口直径小于出油口直径

C.小于出油和进油口直径

D.等于重力环外径