活塞式压缩机的理想工作循环包括（）。
A、吸气过程
B、压缩过程
C、排气过程
D、膨胀过程
参考答案：A, B, C
汽车碰撞时，产生的碰撞力及受损程度取决于事故发生时的状况。
The traffic police stopped three trucks heavily loading with merchandise that looked as grain bags.
A．that were loading... like
B．loaded with... like
C．to load with... for
D．loaded with... for
