单项选择题
The valve that prevents water from backing out of the boiler into the feed line is the（）.
A.bottom-blow valve
B.skin valve
C.feed-check valve
D.feed-stop valve
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相关考题
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单项选择题
The mechanical exhaust valve operation system is replaced by（）in an electronic controlled ME engine.
A.a system with a Hydraulic Power Supply (HPS) unit
B.a system with roller guides for exhaust valves
C.a system with an electronically controlled Alpha Lubricator
D.a system directly powered by electric motor -
单项选择题
（）is not a feature of the electronic controlled engines.
A.Lower fuel consumption
B.Better balanced cylinder power
C.A shorter overhaul period
D.Less smoke emission -
单项选择题
If a camshaft-less engine has a normal injection pressure at rated speed, the injection pressure will be at slow speed（）
A.too low
B.a little lower
C.a little higher
D.exactly the same
