The best ______ to come to Yichang is spring.
I think so. The green water and green mountains are unforgettable. ( )
A.environmentB.journey
C.temperatureD.season
点与圆上任一点连线的中点的轨迹方程是().
已知点在直线上,那么的最小值为()
若直线与圆相交,则()
已知圆的方程为,则圆心坐标为 ()
设直线过点,其斜率为1,且与圆相切,则的值为 ()