One reached down to pick up a stone, then several others.

A young boy picked up a stone and threw it at her.

He turned round, saw me and picked up a stone.

She picked up a stone and tossed it into the water.

Without knowing why, he bent down and picked up a small stone.

It's true that some of these children may have picked up a stone or a gun.

I told Jane that this boy, with nothing better to do, would pick up a stone, as boys will.

Without thinking he reached down and picked up a large stone.

He picked up a stone and placed it right at her feet.

Which is to say he wanted to pick up a stone.