题目

We spent many years studying the formation of rocks , experiencing many sufferings and even death. But our hard work ____________in the end , and we made it. A. came out         B. paid off     C. made up    D. gave away 答案：B已知集合A={（x，y）|x=n，y=na+b，n∈Z}，B={（x，y）|x=m，y=3m2+12，m∈Z}．若存在实数a，b使得A∩B≠∅成立，称点（a，b）为“￡”点，则“￡”点在平面区域C={（x，y）|x2+y2≤108}内的个数是（　　）A．0B．1C．2D．无数个