We are out of time. 我们没时间了。

be out of  没…，…用完了

run out of  …快没了，快用完了

We are running out of time. 我们快没时间了。

We are out of gas.（车）没油了。

We are running out of gas.（车）快没油了。

We are out of toilet paper.没厕纸了。

We are running out of toiletpaper.厕纸快用完了。