单项选择题
The reciprocating pump can’t draw water from a tank may be caused by （）.
A.leaky pipe B.opened inlet valve C.too much water in tank D.None of the above
单项选择题 （）sometimes called filter, is a device designed to prevent the passage of unwanted solids into the system.
单项选择题 Hydraulic pumps most commonly used in steering systems are of the （）.
单项选择题 When an auxiliary boiler is panting and emitting black smoke, you should （）.
