题目

阅读材料：在平面直角坐标系中，点到直线的距离公式为．例如：求点到直线的距离．解：由直线知，，，，∴点到直线的距离为．根据以上材料，解决下列问题：问题1：点到直线的距离为__________；问题2：已知是以点为圆心，1为半径的圆，与直线相切，求实数的值；问题3：如图，设点为问题2中上的任意一点，点、为直线上的两点，且请求出的最大值和最小值． --- Is there anything wrong , Tom ? You look upset .---Oh, nothing . In fact , I ______ the coming National College Entrance Examination .A. have just thought of B. was just thinking ofC. will just be thinking of D. would just think of