阅读下面诗歌，按要求回答问题。
                                                                                               早 梅
                                                                                             唐·张渭
                                                                           一树寒梅白玉条，迥临村路傍溪桥。
                                                                           不知近水花先发，疑是经冬雪未销。

—No, she hasn't been ________there before.

如图，在平面直角坐标系内，点O为坐标原点，直线y= $\frac{1}{2}$ x+1与抛物线y= $\frac{1}{2}$ x²+bx+c交于A，B两点，点A在x轴上，点B的横坐标为4．