读“山脉两侧的地形区”图,该山脉是( )
A:秦岭
B:昆仑山脉
C:天山山脉
D:大兴安岭
如图,C是以AB为直径的⊙O上一点,已知AB=5,BC=3,则圆心O到弦BC的距离是()
This photo reminds me the days when I worked the farm with my classmates.