Trees are useful to man in three very important ways.树对人类有三种重要的作用The first important way is that they not only provide man with food,第一种不仅提供给人类食物but also many animals with food.而且给许多动物食物Without trees many animals could not live on the earth.如果没有树很多动物都不能在地球上生存It's not easy foe man to live on the earth,either.人类在地球上生活也就不容易了.
The second important way is that trees give us shade.第二种,树给我们遮阴On a hot summer day,在炎热的夏天people are eager to have a rest under the shade of a tree after they have walked a long way.人们在走了很长的路后渴望在树荫下休息You can imagine how important the shade of a tree is to man and to animals.你可以想象树荫对人和动物是多么的重要.
The third important way is taht trees help to prevent and floods.第三,树帮助预防洪水However,in many parts of the world,然而,在世界上许多地区man has not reallized the third important way.人类还没有认识到这种重要性He has cut trees down in large numbers.In the end he finds that he has lost the best friends he had.他们砍伐了许多树.最后他才发现他失去了他最好的朋友.