justify

我实在找不到理由再请一天假。

I can't really ___justify taking another day off work.

对成功的渴望并不能成为粗鲁行为的正当理由。

A desire for success does not ___justify rude behavior.

他试图通过解释困难的处境来为自己辩护。

He tried to ___justify ___himself by explaining the difficult circumstances.