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... 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. Should I use "did you know" or "do you know" to introduce a fact? I've only seen "did you know" in action. My logical deduction is that before the "question" (which is not much of a question because you're not asking for an answer), you wouldn't have been sure whether the listener'd known about what you're about to say or not.
how to know if you have vertigo, Is it correct to say the following? I let you know that I have sent you a letter. Or is there a better way to say this sentence? For example: I inform you that I have sent you a letter. MarketWatch: Understanding Vertigo: How to Tell If Your Dizziness Comes from Your Inner Ear or Your Brain Understanding Vertigo: How to Tell If Your Dizziness Comes from Your Inner Ear or Your Brain Vertigo is an intense sensation that your surroundings are spinning or moving uncontrollably, even when you are standing still.
how to know if you have vertigo, It is a symptom of an underlying issue affecting the brain or inner ear. "Know about" vs. "know of" - English Language & Usage Stack Exchange
