横向
1
Large natural stream of water
3
Total number of people in an area
4
Large slow-moving mass of ice
10
Flat grassland in tropical regions
纵向
2
Goods sold to another country
5
Region near the equator
6
Deep narrow valley with steep sides
7
Cold treeless Arctic plain
8
Wearing away of land by water or wind
9
Landform where river meets the sea