What is the correct usage of phrase you don't know what you don't know? I know how to drive a car. Possibly, i do know that can in fact only be used, when, you are answering the question of whether or not you know the issue at hand (or your knowledge has been called in.
I already know how to turn on the television. Recently one of my friends told me that there is distinct difference between 'know of something' and 'know about something' expressions. I know (about) this difficulty/problem.
I saw this sentence in the book 1q84: You would use the present perfect to express something that happened previously, without specifying the time. 'know of' is used when you have personal. Can it be used in formal conversation/writing?
In (2), however, the object of. Why would you have a problem with this? It's not just you that don't know. Please let me know as soon as you figure it out.
However, i am having trouble figuring out why (or whether) this is the correct way to write the sentence,. In the first sentence, it seems to me that to know expresses that the speaker experienced the problem/difficulty.