I have to know exactly why it is I'm doing a particular job.

我必须确切地知道我为什么做某项工作。

《柯林斯英汉双解大词典》

I know exactly how you feel.

我完全了解你的感受。

youdao

Since we are friends, I know exactly how she feels now.

既然我们是朋友，我完全知道她现在的感受。

youdao

Let us say I want to sell my car but I do not know exactly how much it is worth.

VOA: special.2009.04.12

Obviously we don't expect you to know exactly what the distances are, but you should be able to compare them relatively.

当然我们不要求你么,要能知道具体这些位置是多少，但你们要能够相对比较它们。

麻省理工公开课 - 化学原理课程节选

and your hairstylist says, "Oh, I know exactly what to do. We should make your hair blonde."

你的发型师说，“哦，我知道该怎么做。我们要把你染成一头金发。”

I'm afraid of 课堂 - SpeakingMax英语口语达人

Strong personalities who know exactly what they want can be very successful at large universities.

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"The boys know exactly where the Twickenham game stands in our thoughts, " he noted.

BBC: Moseley can cause upset - Smith

We, as a Commission, would need to know exactly what Members' priorities are in that sense.

BBC: Mugshots and making headlines