学进去

It was Saturday morning. Li Ping ______ no class. He ate breakfast and went out. He was going to see a good friend of ______ His friend was ill in bed. Now Li Ping was on his ______ the hospital. There was a river in front of ______. He walked along the river ______. It was not wide. He saw a board ______ the river. Li Ping walked onto the board. But he fell into the river. "Help! Help!" He ______ It was early in the morning. No one came. There was no one ______ there. At last, he got up. The river was ______ very deep. It only came to his waist. He climbed out of the water and ran to ______.