四行程发动机按其四个行程的不同作用分别称为进气行程、压缩行程、作功行程、排气行程。（）
参考答案：对
To greatly raise people's living conditions, ______. [ ]
A. all kinds of measures have taken
B. they have taken all kinds of measures
C. it is said that they have taken all kinds of measures
D. I think they have taken all kinds of measures
什么是逻辑设备，什么是物理设备如何实现从逻辑设备到物理设备的变换这样做有什么好处
