VGCS就是要实现多个人可以讲话,更多的人可以作为听者的业务,那么,系统最多允许多少个人同时讲话()
A.6个
B.8个
C.12个
D.无限制
参考答案:A
—Mr. Smith always has _______ to tell us. [ ]
A. some good pieces of news
B. some pieces of good news
C. some good piece of news
D. some piece of good news
简述超滤工作原理。