Key words & phrases:
planet, billion, total, increase, surface,Indian, Atlantic,Arctic, in total, one third, be covered with..., two thirdsKey sentences:
1.Can you point them out?
2.The earth is a very special planet, and it faces a bigproblem.

3.In the year 2010, the world's population was over 7billion in total.
4. It is increasing very quickly.
5.And by 2050, the world's population may reach 9billion.
6. We can't live in water, and only about one third ofour planet is land.

7.Antarctica is covered with snow and ice all yearround.
8.The earth is our home now,and it will be ourhome in the future.
9. It has the highest point on the earth in theHimalayas.