Joe liked hunting very much. Last month he came back from Africa and said that he would not go hunting any longer. He told me his experience as follows(如下). One morning I was walking in the forest and suddenly saw a lion hidden in the grass, less than three metres away. With a terrible roar(吼叫), he leaped(跳跃)toward me. I aimed my gun at it and shot. But I had no practice in shooting at moving objects at such a short distance. I didn't hit him. Only by the grace(恩典)of God, the lion made such a long leap that he went flying over my head and landed five metres away from me. Just then another hunter came running and the lion quickly ran away from me. I returned to the camp and began to practise shooting at moving objects at short distances. It was going well and I was anxious to find some animal as my target. What I saw later was much dreadful and made me decide to give up hunting. I looked up over the fence, and there at the edge of the forest was the same lion. The lion was practicing short jumps. Joe came back from Africa and decided to give up hunting because ______.