A、B两质点从同一地点运动的x-t图象如图所示，下列说法中正确的是

A．A、B两质点在4s末速度相等

B．前4s内A、B之间距离先增大后减小，4s末两质点相遇

C．前4s内A质点的位移小于B质点的位移，后4s内A质点的位移大于B质点的位移

D．A质点一直做匀速运动，B质点先加速后减速，8s末回到出发点

The old woman has _______________ too many hardships in the past 10 years．

A．broken through

B．gone on

C．broken down

D．gone through