测量实际制冷系统压缩机吸气口温度的目的是为了帮助决定运行工况图上的过（）。
参考答案：热温度点
Jim with his friends many places in China. [ ]
A. visited
B. have visited
C. has visited
D. are visited
电气化铁道用避雷器的额定电压UT为（）。
A、42≤UT≤84
B、60≤UT≤207
C、90≤UT≤468
D、5≤UT≤108
