Getting an apology from him was like getting blood from a stone.

让他道歉几乎是不可能的。

《牛津词典》

One cannot get blood from a stone.

石头里抽不出血。

youdao

Let's face it, your code is already well written and well tuned; getting any performance gains there is going to be like getting blood from a stone.

事实是，你的代码已经写得很好并且很好地调整过，从那里获取性能增益会好比从石头中获取血液一样艰难。

youdao