选择方框里词的适当形式填空。

over ,   earth  ,  thousand , to  , wet

Rainforests cover 6 % of the   surface. Many animals live in rainforests. Quite a lot of them live in the trees 　　　30 meters from the ground. There are lots of tall trees and   　of other different plants. It’s always dark and hot in rainforests and the ground is always   .
Rainforests are very important    us. They are the lungs of the earth. The plants in the forests help to make the air fresher.