3)
1. Whose sister studies English at the college?
2. Who studies English at the college?
3. What does his sister study at her college?
4. Where does his sister study English?
1. Who can order and pay for goods using their credit cards on the Internet?
2. What can computer users do using their credit cards on the Internet?
3. Where can computer users order and pay for goods using their credit cards?
4. What can computer users do to order and pay for goods?
4)
1. Why haven't you read this magazine yet?
2. We shall listen to the music at the theatre tomorrow evening.
3. His father went on a business trip last week.