fait

After the ceremony a marriage is a fait accompli.

婚礼后, 婚姻便是既成了。

We got married secretly and then presented our parents with a fait accompli.

我们是秘密结婚的,后告诉父母。

I was new at the school and not yet au fait with its customs.

我新到这所学校，不熟悉它的规矩。