What I do is that I select a hard stone hammer.

我要做的是，我选择一个坚硬的石锤。

youdao

A cave bat, which regularly lives on a hard stone ceiling, is more careful about its landing preparation than a bat more accustomed to landing in leafy treetops.

洞穴蝙蝠通常生活在坚硬的石头天花板上，它比习惯降落在枝叶繁茂的树梢上的蝙蝠要更小心地做好着陆准备。

youdao

And what I do is, I select a hard stone hammer, in this case a quartzite pebble about the size of a cricket ball, and I elect to hit it in one place - and this is where I start to knap.

我要做的就是，选择一块够硬的石锤，这次我选这块是个头有板球大小的石英岩卵石。先挑个地方锤下去，接着我就开始从这地方开始凿了。

youdao

In your pain and sadness, you may decide that the person you loved is hard-hearted, and in fact,has a heart of stone.

VOA: special.2010.07.18

Like a cherry with a stone inside, if you press it too hard, the stone will fly out.

BBC: Eurovision 2012: Azerbaijan's gays not welcome at home

Being struck hard with a stone cobble might produce this type of injury, the researcher told BBC News.

BBC: 'Earliest' evidence of human violence

It's here that a Kurd named Abdullah Aslan is hard at work rebuilding the roof of a long-abandoned stone hut.

NPR: Turkey Threatens Economic Sanctions on Kurds