Sentence 1: Zac thought he was the best at every athletic activity. 
 Sentence 3: He challenged her to a race down the mountain 
 Sentence 4:  He was shocked and angry when she beat him 
 Sentence 5:  He didn't know she had been a ski racer when she was a teenager 
 Option 1: He and his new girlfriend went to play basketball. 
 Option 2: He and his new girlfriend went skiing together.