Điềm từ còn thiếu vào chỗ trống:
waterfall lake forest cave desert island valley river
1. A large area of land with almost no water, rains, trees, or plants
2. A large area of water that flows towards the sea
3. A large area of water that is surrounded by land
4. A piece of land that is completely surrounded by water
5. A place where a stream or river falls down from a high place
6. A large area of land that is covered with a lot of trees
7. A low area of land between mountains or hills
8. A large hole in the side of a hill or under the ground