单项选择题
One of the main functions of wearing rings, as used in a centrifugal pump, is to （）.
A.maintain radial alignment between the pump impeller and casing B.absorb all impeller shaft end thrust C.prevent water leakage to the atmosphere D.prevent wear of the pump casing and/or impeller
单项选择题 Brine density in a distilling plant is measured with a/an （）.
单项选择题 Which of the following statements is correct regarding an oil with a high viscosity index?（）
单项选择题 If you were operating a centrifugal water service pump with worn wearing rings, the （）.
