压榨脱水后，（）卸荷，活塞杆退回，滤板松开。
A、锁紧油缸
B、主油缸
C、辅油缸
D、液压马达
参考答案：B
There is only _____ traffic in the street of the small town. But the traffic is very busy in the big city. [ ]
A. much
B. a few
C. a little
D. few
