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。

《牛津词典》

But he added that the overall research in this area is "still in its infancy" and one key question is whether literary fiction really is better than other fiction.

但他补充说，该领域的整体研究“仍处于起步阶段”，一个关键问题是，文学小说是否真的比其他小说更好。

youdao

Now comes a key question.

现在有一个关键问题。

youdao

Analysts say a key question is whether Russia will continue to insist missile defense be linked to the conclusion of an arms-control agreement.

VOA: standard.2009.07.15

Should we conclude,therefore, that the key to the important question--namely, What matters? the answer to that question, should we conclude,is,same personality?

我们是否就该得出结论，重要问题的关键，也就是什么是最重要的，这问题的答案就是相同的人格吗？

耶鲁公开课 - 死亡课程节选

What I'm considering right now is the question whether sameness of soul is the key to being the same person.

我现在考虑的问题是,同样的灵魂,是否就是成为同一个人的关键。

耶鲁公开课 - 死亡课程节选

Given these strong gains, the key question is whether the stock still offers good growth potential.

FORBES: Magazine Article

However a key question is will 2013 earnings come in as expected or fall short.

FORBES: Move up http://i.forbesimg.com t Move down

The key question is: where are people getting the money to pay down this debt?

FORBES: New Normal Or Different Normal?