题目

已知直线x－2ay－3＝0为圆x2＋y2－2x＋2y－3＝0的一条对称轴，则实数a＝_______． 答案：1         任务型阅读【1】Our dance club wants a dancer. If you are interested in dancing, you can join our club.【2】We need five students to help repair bikes for students in our school.【3】Our college radio station needs four reporters. If you have experience in it, you can join us.【4】Our school soccer team wants two coaches. If you want to get the job, please call 88556677.【5】Our city library needs a librarian. We want a woman.A. Celina started to learn to dance when she was five years old. She dances well. She wants to join a dance club.B. Sam was a soccer player one year ago. He wants to work as a soccer coach.C. Jerry is interested in reporting and he has much experience. He was a news reporter when he was in high school.D. Ken is good at writing. He has published two books. He wants to be a famous writer.E. Victory can repair bikes. He learned to mend bikes from his father. He wants to help the students repair their broken bikes.F. Jenny is 35 years old. She is a quiet woman and she used to work for a school library.