我们有一个默契，不在他母亲面前讨论这个话题。

We have an ___understanding that we don't discuss the subject in front of his mother.

我们之间有一个非正式协议，平摊账单。

There's an ___understanding between us to split the bills equally.

他们达成一个谅解，不争夺相同的客户。

They reached an ___understanding not to compete for the same clients.