（）是速度型压缩机
A、螺杆式制冷压缩机
B、滑片式制冷压缩机
C、涡旋式制冷压缩机
D、离心式制冷压缩机
参考答案：D
请简述制定工作承办周期应考虑的因素。
The wise parents can tell whether their children are telling the truth __________ they listen
to their excuses to wrong deeds. [ ]
A. the first time
B．for the first time
C．every time
D. for every time
