Trees are very helpful for 1._____ (人)and animals. The trees can give the Oxygen(氧气) that people and animals breathe.

The trees also can clean the air and 2.____ (make) our environment(环境) more beautiful. The 3._____ of the trees can hold the ground. The leaves and trunks of the trees can stop the sandstorm. We also can use some kinds of trees to make pills. Some 4._____ that we eat are from trees, and we can use wood from trees to 5.____ 6._____, too. In 7.______, when you feel very hot, the trees will offer the shadow(阴凉), it can make you cooler. So the trees are our good friends.