Grammar Query (copula placement)

[colloquium]

Can anyone give me their opinion on the underlined section of the two sentences below? Sentence one is correct, and I am trying to find a rule to explain why (it is just the underlined section which needs directly explaining).

To me, it seems like a simple case of the subject (it) having to be before the verb (was) as the sentence is a statement; however I feel that I'm missing something.

Any comments would be greatly appreciated.

I don’t know when it was exactly that I realized my English was good enough to do first certificate...

I don’t know when was it exactly that I realized my English was good enough to do first certificate...

[naomimalan]

Can anyone give me their opinion on the underlined section of the two sentences below? Sentence one is correct, and I am trying to find a rule to explain why (it is just the underlined section which needs directly explaining).

To me, it seems like a simple case of the subject (it) having to be before the verb (was) as the sentence is a statement; however I feel that I'm missing something.

Any comments would be greatly appreciated.

I don’t know when it was exactly that I realized my English was good enough to do first certificate...

I don’t know when was it exactly that I realized my English was good enough to do first certificate...

The second one is wrong because it has the word order of a direct question: When was it that you realized.... ?

The first one is correct because it has the word order of an indirect question, which it is. It doesn't look like a textbook example of an indirect question but it is one.