When I was very small, I could see many birds flying in the sky when I looked at the sky, but as I grow up and move to the city, I find less birds in the sky.

When I was very small, I could see many birds flying in the sky when I looked at the sky, but as I grow up and move to the city, I find less birds in the sky. It is because the environment has been polluted and many birds are dying. We can do small things to protect the environment, so that the animals can live with us. 
在我很小的时候，每当我仰望天空的时候，我都可以看到许多鸟在天上飞，但是当我长大后，搬到了城市，我几乎没见过有鸟儿在天空中飞。因为环境被污染了，许多鸟面临死亡。我们要做些小事来保护环境，让动物能和我们共存。