单项选择题
Brine density in a distilling plant is measured with a/an （）.
A.psychrometer B.salinometer C.anemometer D.sphygmomanometer
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 （）.
单项选择题 The packing installed in the pump stuffing box is lubricated by （）.
