题目

（北京卷26）. --I'm sorry, but I don't quite follow you. Did you say you wanted to return on September 20?    --Sorry, I      myself clear. We want to return on October 20. A. hadn't made     B. wouldn't make    C. don't make        D. haven't made 答案：D如果多项式x2+5ab+b2+kab﹣1不含ab项，则k的值为_________-