题目

This painting     to a museum in New York in 1977. A. sells    B. sold   C. was sold           D. is sold 答案：C 解析: 略已知抛物线C：y2=4x，直线l：y=x+b经过抛物线的焦点且与抛物线交于A，B两点，求：△OAB的面积（O为坐标原点）．