题目

Your camera is quite nice. Where did you buy          ? I want to buy          , too.     A. it; one      B. it; it   C. one; one     D. one; it 答案：A已知非零向量，和满足（+）•=0，且=，则三角形ABC是（ ）A．等边三角形B．等腰非直角三角形C．非等腰三角形D．等腰直角三角形