Safety comes first. We should        to keep safe on the road.

① obey the traffic rules

② be careful of passing cars and buses

③ run fast after others

④ not read the messages on our mobile phones

⑤ play basketball with your friends

A．①②④

B．①③⑤

C．②④⑤

D．②③④

在信息量的计算过程中，出现概念小的事件信息量会（）。

A.比较小

B.比较大

C.不大不小

D.其他选项都不对