VPI指的是（）.
A、虚通路标识
B、虚通道标识
参考答案：A
-How many ____ are there on the table7
- four. [ ]
A. bananas; There are
B. bananas; There is
C. banana; There are
---I’m going to Vietnam?
---How long ___ you___ in Vietnam?
A．are; stayed
B．are; staying
C．have; stayed
D．did; stay
