题目

二次函数的图象与x轴有两个交点，则k的取值范围（   ）A．k<3          B．k<3 且k≠0      C．k ≤3        D．k ≤3且k≠0   答案：B解析:略 4. — Why didn’t you take a bus?—Because it took a long time (wait) for one.