甲、乙两物体在做直线运动，t=0时刻它们从同一地点出发，v-t图象如图，下列说法正确的是（　　）

A．甲、乙在t=8s时相遇

B．4s-8s时两物体越来越近

C．甲的加速度为1.25m/s²

D．甲追上乙时速度等于10m/s

---- Do you _____ any difficulty ______ the subject ?

------ Yes. It’s too hard for me.

A．take; to understand

B．have; in understanding

C．take; understanding

D．have; to understand