A:an=3n−3
B:an=3n−1
C:an=3n+1
D:an=3n+3
–How far is it from the railway station to the hotel?–It's about ______ walk.
读亚洲地图, 亚洲是世界上人口最多的大洲,但人口分布不均。图中甲、乙、丙、丁四个地区相比较,人口相对稀少的是( )