brain|brains

那不可能是正确的方法——用用你的脑子！

That can't possibly be the right way to do it - use your ___brain!

他有脑子，但太懒了不用。

He's got ___brains but he's too lazy to use them.

过度依赖技术可能会削弱我们使用脑子的能力。

Over-reliance on technology can diminish our ability to use our ___brains.