Learn English – “What’s” in indirect questions

indirect-questionsubject-verb-inversionwh-questions

Lets consider the following:

The book doesn't explain, "What's the wisdom behind education?"

Changing this to an indirect question becomes the following:

The book doesn't explain what the wisdom behind education is.

Now, I found many instances on Google where structures like this weren't really converted to indirect questions. For example:

The book doesn't explain what's the wisdom behind education.

"[She] doesn't say what's really on her mind."

Edit:

And consider the following:

What's the logic behind it.

(a) I wonder what's the logic behind it vs. (b)I wonder what the logic behind it is.

(a) sounds better but why?
And are these constructions acceptable?

Best Answer

Grammatically speaking, the last two examples are quite different. In the first example, what substitutes the predicative

The wisdom behind education is something.

What is the wisdom behind education? (question is about the predicative)

I don't know what the wisdom behind education is. <-- correct

I don't know what is the wisdom behind education. <-- too colloquial, unacceptable in formal writing.

Now, in the second example, what substitutes the subject.

Something is on her mind.

What is on her mind? (question is about the subject)

I don't know what is on her mind. <-- correct

I don't know what on her mind is <-- incorrect