单项选择题
A.面向太阳B.背向太阳C.AB都对D.AB都不对
A.延续B.共存C.取消D.无关
A.1500m,3000m,5000mB.2000m,4000m,6000mC.1500m,3000m,5500mD.2000m,8000m,10000m