单项选择题
A.loss of second stage vacuum
B.contamination of the distillate
C.lower feed inlet temperature
D.contamination of the second stage condenser
单项选择题 The pressure of a liquid leaving the pump can be referred to as the （）.
单项选择题 The delivery rate of a variable stroke axial piston hydraulic pump is controlled by varying the position of the （）.
单项选择题 Which of the following statements describes the relationship between viscosity and specific gravity?（）