阅读理解。 My friend has a large dog named Jack. Every afternoon my ffiend takes it for a walk. Jack likes the walk in the park very much. One Sunday afternoon a man came to visit my friend. He stayed a long time. He talked and talked. Soon it was time for my friend to take Jack for his walk. Jack worried about this. It walked around the room several times and then sat down in front of the visitor and looked at him, but he kept on talking. Jack couldn't stand it any longer. He went out of the room and came back a moment later. He sat down again in front of the visitor, holding the visitor's hat in his mouth. Seeing this, the visitor couldn't help laughing. He stood up and said good-bye to my friend in a hurry. 根据短文内容，完成下列句子。 1. The dog, Jack,liked very much in the park. 2. Every my friend takes the dog for a walk. 3. Jack sat down again in front of holding the visitor's hat in its mouth and looked at him in order to tell the visitor that it was time for him to say good-bye. 4.The second paragraph tells us that is very clever.