She gets pregnant after a one-night stand.她在有过一次一夜情之后怀孕了。

He says it was a one-night stand.他说那不过是一夜情而已。

a woman with whom he had had a one-night stand一个和他发生过一夜情的女人

I can only assume I was just a one-night stand.我只能猜测自己仅仅是被当成了一夜情的对象。