物联网的首要设计目标是（）
A.如何实现信息传输
B.新的通信协议
C.能源的高效利用
D.微型化
参考答案：C
I won't tell the student the answer to the math problem until he _____ on it for more than an hour.[ ]
A. has been working
B. will have worked
C. will have been working
D. had worked
郁李仁具有的功效是（）
A.利水消肿
B.养心安神
C.养血活血
D.滋阴补血
E.降气化痰
