题目

设F为抛物线的焦点，A是抛物线上一点， B是圆C：上任意一点，设点A到y轴的距离为m，则的最小值为           ． 答案：2   ；— How is your English study?Not bad. But I_______ learning English grammar.A．am interested in B．am good atC．have a little troubleD．have no trouble