关键的谈判在非公开场合下进行。

The crucial negotiations took place ___behind ___closed ___doors.

这些国际协议往往是在私下里敲定的。

These international agreements are often finalized ___behind ___closed ___doors.

委员会倾向于私下讨论这类敏感问题。

The committee prefers to discuss such sensitive matters ___behind ___closed ___doors.