The function of the heart is to pump blood. ✬

Tom needs at least nine hours of sleep every night or he can't function. ✬

I can't function without you. ✬

I'm unable to function alone. ✬

As far as I know, such a function doesn't exist. ✬

As far as I know, there is no such function. ✬

We can't function like this. ✬

Perfectionists find it harder to function than average people. ✬

Tom's function was to advise. ✬