物联网中（）主要实现信息的传递、路由和控制，包括接入网和核心网。
A.感知层
B.网络层
C.应用层
D.基础层
参考答案：C
如图所示，一束光从直角三角形玻璃砖的AB面垂直射入，并从玻璃砖AC面射出．请画出该过程的光路图．
There was never any time for Kate to feel lonely, _____ she was an only child.[ ]
A. ever since
B. now that
C. even though
D. even as
