单项选择（每题1分）

The stones each _____ as much as two tons.

A．weighs

B．are weighed

C．weigh

D．is weighed

一张旧圆桌的桌面直径是1m，李大爷准备修理一下这张圆桌．他打算在圆桌边缘钉上铁皮，给圆桌的正面刷上油漆．问：李大爷至少要准备多长的铁皮？这张圆桌需要刷油漆的面积有多大？