题目

 It’s my mother’s birthday tomorrow. I will buy ________ a CD as a present. A. him                          B. her                          C. me                          D. you 答案： B 已知实数p、q、r满足r2=p+q，r（r-1）=p•q且0＜p＜1＜q＜2，则实数r的取值范围是________．