story: Kim accidentally took her Dad's lunch to school instead of her own. At lunch time she was horrified to see a sardine sandwich! Tom was sitting near her and begged her to trade with him. She accepted not knowing what she was getting. To her surprise it was her favorite peanut butter and Jelly!
 selected sentence: To her surprise it was her favorite peanut butter and Jelly!
Kim didn't know what sandwich >Causes/Enables> Kim was surprised