没有免费午餐这种事！

There's ___no ___such ___thing as a free lunch!

他声称有魔法药水，但我知道没有这种东西。

He claimed to have a magic potion, but I know there's ___no ___such ___thing.

现实中，没有完美这种事。

In reality, there's ___no ___such ___thing as perfect.