简单介绍Iu、Iub、IuR接口分别处于系统中的什么位置？
参考答案：Iu：[RNC与CN间]
Iub：[RNC与NodeB间]
IuR：[RNC间]
— May I speak to Tom?
— Sorry, he _____ Italy. But he _____ in two weeks. [ ]
A. has been to, will come back
B. has gone to, will be back
C. has been to, would come back
D. has gone to, won't come back
一般叶片泵在（）万帕压力下工作比较合理。
A.25
B.63
C.100
D.125
