unanswered

形容词 unanswered:

1. not returned in kind
   同义词：unreciprocated, unrequited

1. I'm sorry I've left some of your questions unanswered.
   很抱歉，你有些问题我没有回答。
2. Through an unfortunate oversight your letter was left unanswered.
   由于令人遗憾的疏忽，未能给你回信。