V带传动工作时是通过（）接触摩擦，在相同条件下其承载能力远大于平带传动。

A．弧形面

B．楔形侧面

C．平面

D．曲面

If you have lost a library book, you have to ______ it. [ ]

A. find out

B. look after

C. pay for

D. take care