题目

You have seen Mary at the meeting this morning, because she left forBeijing yesterday. 答案：【1】couldn't如图，已知梯形ABCO的底边AO在x轴上，BC∥AO，AB⊥AO，过点C的双曲线y=kx交OB于D，且OD：DB=1：2，若△OBC的面积等于3，则k的值（　　） A、等于2B、等于34C、等于245D、无法确定