Several years ago Robert knew a girl at a party. He loved her at once. But he hadn't enough money to marry her. He went to another village and wanted to borrow five thousand dollars from Peter, one of his classmates. He said he was going to return the money in two years. Peter Black believed him and lent the money to him. And Robert thanked the young man very much. In the past four years Robert married the girl and she had a baby. They lived a happy life, but he didn't give the money back to Peter. One day Peter's mother was ill and needed an operation. He looked for Robert for a few times, but he never met him. One day Peter heard that the young man was in. He hurried there. He knocked at the door for a long time and Robert's wife came out to meet him. "I'm sorry, Mr. Black." said the woman. "My husband has just gone out." Peter thought for a while and said, "Yes, I met him on my way here. He told me that he had left all his money at home and let you return it to me." "Don't believe him, dear!" Robert came out in a hurry  and called out. "I've never told him about it!" Robert wouldn't meet Peter because   _  .
he did not want to pay back the money he had paid Peter all the money he was always very busy his wife didn't let him do so