1. My mother wanted to know who I had seen at the meeting.
Cấu trúc: S + asked/ wanted to know + wh-word + S + V (lùi thì).
2. She asked me if I would like some coffee.
Cấu trúc: S + asked (sb) + if + S + V (lùi thì).
3. She apologized for not writing.
Cấu trúc: S + apologized + for + (not) + V-ing