All the Chinese people         when they heard China win the chance to hold the Olympic Games in 2008.    [ ]

A. are cheering                  

B. cheered    

C. have cheered                

D. cheer

液压梯油缸垂直度在呈90度的两个方向上，每5m不大于（）；同时油缸的抱箍固定应牢固。