Neither my sister nor I __________ been to America before.
A:have ever
B:have never
C:has ever
D:has never
漫画《拆》告诫我们( )
抛物线y=x2﹣4x+c与x轴交于A、B两点,已知点A的坐标为(1,0),则线段AB的长度为____ .
— This is a great chance that many people don't have.
— I see. I'll cherish(珍惜) it.