Subject + verb + interrogative adverb / pronoun + clause
Study the following sentences.
- I know where he lives.
- He asked when he should come.
- I wonder why he is late today.
- She explained how it could be done.
- I know what I should do now.
Note the word order in the clause introduced by the interrogative adverb / pronoun. As you can see, the subject comes before the verb. In typical questions, the verb comes before the subject. But when a question word clause becomes the object of a verb, it has the same word order as an affirmative clause.
- Incorrect: I don’t know what does she want.
- Correct: I don’t know what she wants.
- Incorrect: I know how should it be done.
- Correct: I know how it should be done.
Subject + verb + noun / pronoun + questions word clause
- They asked me what I was doing there.
- He told us when we should start.
- The teacher showed us how it could be done.
- Tell me where I should go. (Here the subject you is not mentioned, but it is understood.)
- I told him why it could not be done.