Mr. Zhou's office is not far from his home, but he drives to work every day. He likes his car very much, so he often washes his car and he uses a lot of water to wash it. He tells Mrs. Zhou, "I must keep my car very clean." Mrs. Zhou says to Mr. Zhou," You shouldn't wash your car too often. You shouldn't waste too much water." Mrs. Zhou goes shopping every day. She goes to the market on foot. She likes walking. She thinks it's good for her health.