He rolled the clay into a ball.

他把粘土揉成一个球。

youdao

Use your hands and work a ball of modeling clay that is approximately the size of your palm into a pancake shape 1/4-inch thick.

用你的手把纸粘土攥成一个球形，在手掌中拍扁了以后大概是个煎饼大小，1/4英尺厚。

youdao

Compress this clay into a small ball.

把这块粘土压缩成一个小球。

youdao

A ball of clay is placed on a flat wheel device that turns quickly.

VOA: special.2009.09.09

People form containers by pressing a ball of clay into a given shape.

VOA: special.2009.09.09

On clay, the ball bounces much higher than on other surfaces, so players have to hit the ball at shoulder level.

BBC: Clay brings tension to surface

But on a high friction surface like clay, the ball will grip more and change the trajectory of the ball quite significantly.

BBC: SPORT | Tennis | Rules and Equipment | On the rebound

The reason: All four of the top American hopes possess serves and groundstrokes which are strong enough to be weapons on any surface, and the slow, high bounce on clay brings the ball into their hitting zone with sufficient time for them to set up their shots.

WSJ: Americans Produce Feats on Clay