That is the crux of the matter.

这是问题的关键。

And this is kind of the crux of the matter.

这就是问题的关键所在。

First, the crux of the matter is for students to pursue a subject that interests them.

第一，学生可以选择自己感兴趣的专业，这是最主要的。

And the crux of the matter is that that the structure of a high rise building is essentially indefinite.

问题的关键在于，高层建筑的结构基本上是不确定的。

But the crux of the matter is where it is suing the company.

但问题的症结在于它起诉公司的地方。

That may come, but you're right, that will be the crux of the matter.

那可能会发生， 但你是对的， 这将是问题的关键。

The kind of main crux of the matter, in terms of the history of English, was 1066, was the Norman Conquest, when suddenly you've got English speakers and  French speakers.

从英语历史的角度来看，问题的关键在于 1066 年， 即诺曼征服时期，突然间就有了说英语和法语的人。