社交场合中的最佳表情是（）。
A、含蓄
B、制怒
C、色温
D、微笑
参考答案：C
---What was Jim wearing at the party?
--- Nothing _______. He was in his usual shirt and jeans.
A．special
B．simple
C．important
D．interesting
EPON在实际应用中传输距离可以大于20KM
