听力原文：W: Yes. It was a year ago that my husband and I decided to change roles. M: Why did you suddenly think of exchanging roles? W: A year ago, I was beginning to get bored at home all day. My husband didn't like his job most of all, he hated traveling to work in the rush hour every day. M: Did your husband agree to stay at home? W: At first, be didn't. But I applied for a job with a salary higher than his. It seemed sensible for me to accept the job and for him to stay at home. M: Now, you've exchanged places for a year. How are you getting on? W: Very well. We choose roles that are comfortable for us. M: How's your husband? W: At first, he really enjoyed staying at home and being with the children. He thinks we made the right decision although lie does find housework very boring. M: What about your marriage life before exchanging roles? W: We have a traditional marriage. I stayed at home to care for children and my husband. My husband worked at a job in the office. M: Did your husband make most of the decisions at that time? W: Of course, he earned the money and paid the bills. Why did Mrs. Smith change her roles with her husband?