静压轴承之所以能够承受载荷，关键在于液压泵在油缸之间有（）。
A、减压阀
B、节流阀
C、整流器
D、溢流阀
参考答案：B
The Town Hall _____ in the 1800's was the most distinguished building at that time. [ ]
A. to be completed
B. having been completed
C. completed
D. being completed
什么叫相对膨胀？
