题目

—Sorry to hurt you. —_______. You didn’t mean to, did you? A.Forget it      B.No problem     C.All right     D.Don’t say so. 答案：A已知数列{an}满足a1=0，an+1=an-33an+1（n∈N*），则a19=（　　） A、0B、-3C、3D、32