横向
1
Wearing away of land by water or wind
3
Flat elevated area of land
5
Region surrounding the North Pole
6
Land surrounded by water on three sides
7
Region between the two tropic lines
8
Distance north or south of equator
9
Large area covered with trees
纵向
2
Physical features of land
4
Deep narrow valley with steep sides
5
Largest river in South America