I am so sorry to repeat my question, but I cannot yet understand it.

Could you please readily or freely explain the difference between these? I can not understand their differences...

I know what is the difference between these.

I know what the difference is between these.

Or, when/where are they interchangeable? And what is the difference between them?

I know who are you

I know who you are

  • 1
    I have a hunch that you might confuse yourself with the examples "I know who my friend is." vs "I know who is my friend."in this previous question. Which, unfortunately, both of them are possible. This question is essentially a duplicate of the previous question. It is just that there seems to be no satisfying answer to you yet. Mar 25, 2014 at 16:34
  • 1
    @DamkerngT. do you mean "I know who my friend is" and "I know who is my friend" both are possible and correct? I thought only one is correct. Apr 3, 2014 at 3:11
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    @Man_From_India "I know who my friend is" is the basic construction. "I know who is my friend", which is also correct (and that's an unfortunate example the OP used in their previous question), emphasizes the difference of who is my friend, and who is not. For example, see books.google.com/books?id=y2_TV8ZJV6YC&pg=PA49. Actually, we use this kind of construction all the time, for example, "I know what is right and what is wrong." Maybe it's just "who" that makes it sound weird. Apr 3, 2014 at 3:18

2 Answers 2


Whatever I said in my last answer is correct, but there needs to be some addition. Here I am trying to explain your question. My first impression was that out of the two quoted example sentences in the original post only one was correct. But after going through the comment of @DamkerngT. I am sure both of the example sentences are correct.

Consider the following example -

Mr A is my friend.

Now if I want to make this sentence interrogative it will be - Who is my friend? The subject is Mr. A. Similarly Mr. A can be the object of the sentence having the same meaning - My friend is Mr. A. And now if we make this sentence interrogative the inversion occurs - Who is my friend?

Your example sentence is not an interrogative one, instead an assertive sentence. So the depending clause also will be assertive.

I know Mr. A is my friend. - I know who is my friend. ( When we make "Mr. A is my friend" interrogative, no inversion occurs. So "I know who is my friend" here also no inversion will occur.)

I know my friend is Mr. A - I know my friend is who - I know who my friend is. ( When we make "My friend is Mr. A" interrogative, inversion occurs - Who is my friend. To make "who is my friend" assertive we inverse again. So it comes down to - I know who my friend is.)

I know this answer is a little bit clumsy, but I didn't find any other way to explain it. Please let me now after reading this answer what all clarification you need.


You should inverse subject-verb when you are asking question. The sentence - I know who you are - is meant to be assertive, not interrogative. So you should keep sub + verb straight. The sentence - Do you know how the patient is - is meant to be interrogative, so make the main clause interrogative ( invert sub + verb arrangement), but keep the other clauses plain assertive, and hence no inversion. I think you got it. Let me know if you have any doubt.

  • First, thank you so much. Moreover, I know almost 90% of it's grammar, but I am confused with meanings of my "original questions".
    – nima
    Mar 25, 2014 at 10:44
  • Did my reply above help? Mar 25, 2014 at 10:48
  • Thank you so much, but I could not find my original answers.
    – nima
    Mar 25, 2014 at 14:37
  • I think that my questions need a more long range answer.
    – nima
    Mar 25, 2014 at 14:37
  • The short answer is that "I know who are you" is incorrect, and as such has no meaning.
    – Jim
    Mar 25, 2014 at 14:52

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