---Do you know _______________________ won high click rate in micro-blogs?

---It was the teachers’ wonderful chorus in the New Year’s gala.

A．what is it that

B．which is it that

C．which it was that

D．what it was that

照明系统的功能有（）。

A.保证行车安全、减少交通事故

B.对不同路段、不同设施的照明，分回路地进行分合控制

C.具有短路、过载等保护

D.有随照度的变化对照明进行调节控制，以节约能源和降低运营费用

E.自动发现线路故障点