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