根据听到的对话和问题，选出正确的答案。 (     ) 1. A. My mother is. (     ) 2. A. Take the No. 21 bus. (     ) 3. A. John. (     ) 4. A. Thirteen yuan. B. My father is. B. By taxi. B. Jenny. B. Four yuan. C. Both my mother and my father. C. On foot. C. John's brother. C. Three yuan. (     ) 5. A. He is going to write a letter to his teacher. B.  He is going to write a letter to my teacher. C.  He is going to buy some paper.