A story tells that two friends were walking through the desert. During the trip they had a 1 ，and one friend hit the other in the face. The one who was beaten was hurt,but without saying 2 ,he wrote in the sand: “Today my best friend hit me in the face. ”
They 3 溺水),but the other friend saved him. After he came back to life from the near-drowning,he wrote on a 4 ：“Today my best friend saved my life. ” on walking,until they found a lake,where they decided to take a bath. The one,who had been beaten,fell into the lake and started drowning(
