体操运动员在单杠上做各种旋转、神屈动作，说明关节在运动中所起的作用是（　　）

A．动力

B．杠杆

C．支点

D．调节

_____ that's important is that you are doing your best and moving in the right direction. [ ]

A. One

B. All

C. Everything

D. Anything