Some of the most important questions remain unanswered.

最重要的一些问题依然没有答案。

Readers should send a copy of unanswered letters to their MP.

读者应该把那些未得到回复的信件复印一份寄给代表他们的议员。

He had always had difficulty leaving questions unanswered.

如果有问题空着没有作答，他总会觉得不自在。