物体A以速度v=3t²+1（m/s）在一直线l上运动，物体B在直线l上，且在物体A的正前方5 m处，同时以v=10t（m/s）的速度与A同向运动，出发后物体A追上物体B所用的时间t（s）为   [ ]

A．3

B．4

C．5

D．6

根据对话内容，选出方框中所给的句子补全对话。

A: You don’t look well today.   小题1:_

B: I’m not feeling well. I have a headache.

A: I am sorry to hear that.  小题2:

B: About two days ago. And maybe I have a fever now.

A: That’s too bad.  小题3:

B: Yes, I think so. I’ll go right now.

A: I hope   小题4:_

B:    小题5:   Goodbye!