What is the right way to embed one question inside another?

For example:

  1. "Do you know what is it?"
  2. "Do you know what it is?"

Are they both grammatical? If one of them isn't, then why is it ungrammatical?

I can say the question "What is it?", so I assume I can also say the question "Do you know what is it?" Can't I?

  • Do you mean "Do you know what is it" and "Do you know what it is"? Dec 10, 2014 at 15:33
  • 1
    This could be a good grammar question, if the appropriate question were* to be asked. -- Aside: The example "Do you who is it?" would be acceptable in the context of children playing the game "Tag". :)
    – F.E.
    Dec 10, 2014 at 19:55
  • Here are some related answer posts that might interest you: ell.stackexchange.com/a/36640/8758 , ell.stackexchange.com/a/38867/8758
    – F.E.
    Dec 10, 2014 at 20:36

3 Answers 3


The rule is: Subordinate questions have no inversion of subject and verb as in independent questions.

So the following examples are correct:

What is it? (Subject placed after the verb)

Do you know what it is? (In the subordinate question normal word order subject verb)


This one is grammatical:

Do you know what it is?

This one is not grammatical (except for an unusual situation described below):

Do you know what is it?

The key to understanding this is to see that what it is is not a question. It's just the object of know. What is it? is a question, but there's only one question here, not a question within a question.

As a declarative statement, you would say:

You know what it is.

Making this into a question requires that you add the auxiliary verb do in front of the subject. That's all you need to do to turn this statement into a question. You don't need to do anything to the object of know.

An exception: As F.E. noted in the comments, there's a children's game called "tag" where one person is called "it". In that game, you might ask "Do you know who is it?" (with the stress on "it"). This is because the equivalent statements are "Johnny is it" and "I know [that] Johnny is it." A more-ordinary form of this is "Do you know who is President?" So, there's probably some rare circumstance where it would make sense to say "Do you know what is it?", but I can't think of one.


I assume the two sentences are

1) Do you know what is it?

2) Do you know what it is?

I kinda do a Google research on this and basically most people say it should be the first one but unfortunately the correct one is the second one.

Why it is so? If we refer to the rule of making question (WH-word + verb to be/verb to have + subject + verb + description). But based on the question above, there are no verb/description after the subject. So, now here the second rule (WH-word + subject + verb to be)

So, here you are. Based on the second rule the second one is right.

1) Do you know what is it? (Wrong)

2) Do you know what it is? (Right)

3) Do you know what is it all about? (Right, as there is a description behind the subject)

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