There are two main kinds of interrogative sentences. Those which start with an auxiliary verb and those which start with a question word such as what, why, when, where, how etc.

The following changes occur when an interrogative sentence in the direct speech is changed to the indirect speech.

Interrogative sentences beginning with an auxiliary verb are changed into the indirect speech by using the connective if or whether.

The reporting verb said (or any other word used as the reporting verb) changes to asked, queried, questioned, demanded of or enquired of in the indirect speech. Note that of is used after enquired and demanded only when the reporting verb has an object.

The most common reporting verbs used to report a question are asked and enquired of. The reporting verb queried is somewhat investigative. Demanded of is the strongest of all reporting verbs mentioned above. It is used when an explanation is desired.

Note that the indirect narration is always in the assertive form. In other words, the interrogative sentences in the direct speech will change into assertive sentences in the indirect speech.

Study the following examples carefully to understand the rules mentioned above.

Direct: She said to me, ‘Are you coming with us?’
Indirect: She asked me if I was going with them. OR She asked them if I was coming with them.
Direct: She said to me, ‘Are you unwell?’
Indirect: She asked me if I was unwell.
Direct: She said to him, ‘Am I to wait for you till eternity?’
Indirect: She enquired of him if she was to wait for him till eternity.
Direct: I said to him, ‘Were you present at the meeting yesterday?’
Indirect: I asked him whether he had been present at the meeting the day before (or the previous day).
Direct: The woman asked the stranger, ‘Should I help you?’
Indirect: The woman asked the stranger whether she should help him.

Note that the auxiliary verbs should, could, would, ought to and might do not change in the indirect speech.

Direct: I said to him, ‘Who are you?’
Indirect: I asked him who he was.
Direct: The mother said to the daughter, ‘Do you know where John is?’
Indirect: The mother asked the daughter whether she knew where John was.
Direct: ‘Have you anything to say on behalf of the accused?,’ said the judge to the lawyer.
Indirect: The judge enquired of the lawyer if he had anything to say on behalf of the accused.