单项选择题
For safe storage, the maximum allowable temperature to which refrigerant bottles should be exposed is （）.
A.100℃ B.125℃ C.150℃ D.175℃
单项选择题 One of the main functions of wearing rings, as used in a centrifugal pump, is to （）.
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?（）
