题目

 He believed that these creatures are linked to a common ancestor, __________ that lived in Asia ______300,000 years ago.    A. who; about         B. which; around         C. one; some   D. an animal; for 答案：C如图，A、B是双曲线y=（k＞0）上的点，A、B两点的横坐标分别为m、2m，线段AB的延长线交x轴于点C，若△AOC的面积为4，则k的值为________．