If the question is not introduced by any question word, but “is” one of the types that can take yes or no for answer, we use conjunction “if” or “whether”.
(i) The girl said, “May I wear this saree, mother?”
⇒The girl asked her mother whether she might wear that saree.
(Note: Whether is a better conjunction since it includes the two meanings if and if not though, being short, if is more frequently used.)
Questions beginning with “shall I”:
Questions beginning with “shall I” are of two types:
(i) He said to me, “Shall I return these notes by Monday?”
⇒He asked me if he would return those notes by Monday.
(ii) He said, “Shall I have a happy married life?”
⇒He wondered if he would have a happy married life.
(i)He said to me, “Shall I post these letters for you?”
⇒He asked me if he should post those letters for me.
(ii) The clerk said to him, “Shall I ask these people to wait for you?”
⇒The clerk asked him if he (clerk) should ask those people to wait for him.
“Yes” or “No” answers to questions:
While changing from direct to Indirect, yes or no are paraphrased: as;
(i) She said to Madam Sultana, “Can you lend me this necklace?”
Madam Sultana said, “Yes”(Direct)
⇒She asked Madam Sultana whether she(Madam Sultana) could lend he that necklace, Madam Sultana replied that she could.
(ii) I said to Asif, “Are you willing?”
Asif said, “No”
⇒I asked Asif if he was willing. Asif said that he was not.
(iii) I Said, “How many discoveries go unheeded?”
⇒I wondered how many discoveries went unheeded.
(iv) I said to him, “Where have you lost the pen, I brought for you yesterday?”
⇒I asked him where he had lost the pen, I had brought for him a previous day.
(v) She said to me, “Is there any possibility of my getting promotion this year?” I said, “Yes”.
⇒She asked me whether there was any possibility of her getting promotion that year. I replied that there was.