小军用绳子拴着一金属小球，使小球做圆周运动，如果小球受到的力突然全部消失，则小球将 [ ]

A．做匀速直线运动

B．立即停止运动

C．继续做圆周运动

D．减速运动直到停止

Practising Chinese kung fu can not only__________one's strength, but also develop one's character.[ ]

A. bring up    

B. take up

C. build up  

D. pull up