unanswered
adj. 未答复的；无反应的
例句
Some of the most important questions remain unanswered.
一些最重要的问题仍未被答复。
《柯林斯英汉双解大词典》
Many questions about the crime remain unanswered.
这桩罪行涉及的许多问题仍然没有答案。
《牛津词典》
The key question of what caused the leak remains unanswered.
泄漏究竟是怎么造成的，这一关键问题仍未得到答案。
