完形填空
There1many islands in the sea. In its warm waters there are some little2. We call them "coral Islands（珊瑚岛）".
A coral island looks3a ring of land (一圈陆地) with trees, grass, and flowers on it. One part of the ring is open to the water. There is4little round lake inside the island.
5you look into this lake, you will see beautiful coral. You may think they are flowers. If you look at a piece of coral, you will see many little holes in it. In each of these holes a very small sea animal has lived. These sea animals6the coral.
They began to build under the water. Year after7, the coral grew higher and higher. At last it grew out of the water.
Then the sea brought it small trees and something8. After some years, these things changed into earth. Sometimes the wind brought seeds (种子) to this earth. Sometimes birds flew over it and brought9to the island.
The little seeds grew. In a few years there were plants all over the island. In a few more years there were trees growing there.
So you see, these islands were built little by little. The workers were very small. Do they not teach us a lesson? Can you think10the lesson is?