Recently one of my friends told me that there is distinct difference between 'know of something' and 'know about something' expressions. 'know of' is used when you have personal experience with wha...
"Know about" vs. "know of" - English Language & Usage Stack Exchange
Why do you think that He doesn't know him from his schooldays means that he does know him? It would only have that sense if you added something like In fact, he first met him at university.
Why? Because you've just told them! It's like when saying "Did you know strawberries aren't berries, but bananas are?", I didn't know if you'd already known about that factoid prior to my "question", but at the time I say it onward, I know you know it because I've just told you. Therefore, it'd be reasonable to use the past tense with "did".
Should I use "did you know" or "do you know" to introduce a fact?
What is the correct usage of phrase "you don't know what you don't know"? Can it be used in formal conversation/writing?
I saw this sentence in the book 1Q84: It's not just you that don't know. However, I am having trouble figuring out why (or whether) this is the correct way to write the sentence, as opposed to: ...
"doesn't know" vs "don't know" [duplicate] - English Language & Usage ...