(Not) to, so as (not) to, in order (not) to.
1.Ed took some change from his pocket. He wanted to buy a newspaper.
=> Ed took some change from his pocket in order to buy a newspaper.
=> Ed took some change from his pocket to buy a newspaper.
=> Ed took some change from his pocket so as to buy a newspaper.
2. I wanted to listen to the news while I was making dinner. I turned on the TV.
=> I turned on the TV to listen to the news while I was making dinner.
=> I turned on the TV in order to listen to the news while I was making dinner.
=> I turned on the TV so as to listen to the news while I was making dinner.
3. I'm studying hard. I want to keep pace with my classmates
=> I'm studying hard so as to keep pace with my classmates.
=> I'm studying hard to keep pace with my classmates.
=> I'm studying hard in order to keep pace with my classmates.
