题目

Dear Mrs. Smith, I was a student of yours in Grade Six, and I hope you still remember me．I’m writing this letter because I want to let you know that the school year with you was important and special to me．It made a big contribution（贡献） to my life． I know I was very quiet in your class，and you never said much to me．But you did something that made a big difference in my life．You see，all through my first year in schools，I hated to read．Books were just words that had very little to do with me, and I was bored by them．I’ll never forget the first day of Grade Six whe函数f（x）=的定义域是（ ）A．[-1，+∞）B．（+∞，]C．（-∞，-1]D．（-1，0]