我们之所以不太了解它们，是因为它们已经完全消失了。

The reason we don't know about a lot of them is that they have vanished entirely.

youdao

法官大人，我之所以提出这一点，是因为我认为了解被告的背景是很重要的。

I bring this up, your honour, because I think it is important to understand the background of the defendant.

《柯林斯英汉双解大词典》

她的演说之所以令人难忘，不是因其内容而是因其辩论方法。

Her speech was memorable for its polemic rather than its substance.

《牛津词典》

Is Milton powerful for the very straightforward reason that he's in possession of this tremendous literary strength, this unimaginable talent?

弥尔顿之所以强大是因为他有,无穷的文学力量，不可想象的天赋这显而易见的原因呢？

耶鲁公开课 - 弥尔顿课程节选

I think the reason why triathlon is not so, so big is just because it requires a lot of time.

我认为铁人三项运动之所以不够普及，
是因为它需要大量的时间。

对体育项目的热爱 - SpeakingMax英语口语达人

This decision is also hard to make because when you are a backend technology provider, it's like selling a piece of commodity.

之所以这是一个困难的决定还因为,当作为后台技术提供商时，就像出售一件商品似的。

斯坦福公开课 - 百度CEO李彦宏演讲：全球最大搜索引擎的发展课程节选