事故究竟是怎么发生的不是很清楚。

It's not clear precisely how the accident happened.

《牛津词典》

一周前拍摄的视频图片不是很清楚。

The video pictures taken a week ago were not very clear.

youdao

你知道，我仍然不是很清楚水文循环，也就是水在地球和大气之间的来回转移。

You know, I am still not too clear about the hydrologic cycle, the transfer of water back and forth between the earth and the atmosphere.

youdao

So the writer seems very determined to tell the story in a way that depicts God as acting not capriciously but according to certain clear standards of justice.

作者似乎决定,描述不是一个变幻莫测,而是有着很清楚公正原则的上帝。

耶鲁公开课 - 旧约导论课程节选

Now, I'm fully aware that this is not the flashiest example in physics, but I'm not worried about that right now.

我很清楚,这个并不是物理学中最经典的例子,但是这并是我现在的担心

耶鲁公开课 - 基础物理课程节选

I don't know. Does anybody--It has been-- The colleague answered and said that it's not as effective as other methods.

我不是很清楚,有同事回答说,这种方法并不如其他方法有效

耶鲁公开课 - 心理学导论课程节选