story: Katie's birthday was coming up. Her best friend wanted to surprise her with a party. She got together with Katie's friends and family and made a plan. They decided to have Katie go to the store while they set up the party. They set up the party and surprised Katie when she came back.
 selected sentence: They set up the party and surprised Katie when she came back.
They want(s) to surprise Katie >Motivates> They set up the party