Possible duplicate of "Know about" vs. "know of". Also What are the differences between “know”, “know about”, and “know of”?

Context Explanation

on English Language Learners, which is probably a better site for questions like this. 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.

Insight Material

In my understanding, ' as we know it ' usually follows a noun phrase and means like The building as we know it = the version/condition of the building we know now. First, I'm not sure about its grammar. Is the 'as' a conjunction? Is it correct to think that 'it' changes to 'them'? E.g., the buildings as we know them Second, a question about its use.

Final Conclusion

Is it possible to use when the preceding ... 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 to question, and you are answering that challenge). Let's say "out of the blue" you wanted to state that "you know that" -- and you wanted an emphatic version. Rumors have been circulating about Apple's next iPhone for quite some time. Here's what we know about the iPhone 18 so far. MacRumors: iPhone Air Sales Are So Bad That Apple's Delaying the Next-Generation Version iPhone Air Sales Are So Bad That Apple's Delaying the Next-Generation Version