No - I don't know what the 26th brightest star in the constellation of Rigel is called. That's a known unknown (to me). A question I know has an answer, which answer I do not know. But OP is …

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 …

Can anyone give use cases and examples for Happen to know Came to know Got to know Came across I always gets confused in their uses.

I don't know exactly what a double-positive makes a negative means, but I don't think I agree with it. Nor do you, judging by the next sentence.

My question is about similar (for me) question forms "don't I know you" and "do I know you". Is there any difference between them or can they both be used in the same context without any …

For me, know implies knowledge of details or individual pieces, while am aware of implies a knowledge only of a whole. Using your example, knowing my rights means that I know I have …

If someone has stated that they don't know something, and you are stating you don't know that same something, you would would use "I don't know either." The only situation where "I also …

I am a non-native speaker of English. When communicating with a professor, would it be better to use could you kindly send me the document or could you please send me the document? I …

Therefore, saying "did you know" asks if you have previously known something. "Do" is the present tense, so saying "do you know" would ask if you currently know.

Possible duplicate of "Know about" vs. "know of". Also What are the differences between “know”, “know about”, and “know of”? on English Language Learners, which is probably a better site …