题目

 ---- Would you mind answering some questions on shopping habits? ---- ________________.A.Yes, with great pleasure.       B.No, I’m afraid I can’t make it.C.Yes,it is worth the time.        D.No,as long as it doesn’t take long. 答案：D当a<0时,不等式42x2+ax-a2<0的解集为(    ) A.{x|<x<-}                           B.{x|-<x<} C.{x|<x<-}                          D.空集