单项选择题
The domestic fresh water pump starters are controlled by pressure switches which operate when the pressure in the tank varies within predetermined limits as water is drawn offThe word “which” means （）.
A.starters
B.pressure switches
C.pressure
D.water
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相关考题
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单项选择题
In general, domestic flesh water tank kept under pressure by an external supply of （）.
A.forced circulating pump
B.compressed air
C.gravity tank
D.bead tank -
单项选择题
The abbreviation "TDS" about the potable water probably means （）.
A.total dissolved solids
B.temperature of distillation of sea water
C.total dissolved sodium
D.total delivery system -
单项选择题
A condenser is a vessel in which（） is deprived of its latent heat of vaporization and so changed to its liquid state.
A.sea water
B.fresh water
C.vapour
D.gas
