隨著經濟的快速發展，大城市中的高樓越建越多，道路越修越寬，但樹木卻越來越少。以國慶五十周年為契機，國家號召各大城市努力整頓市容，拆除違章建筑，增加綠化面積。這無疑是個造福子孫的明智之舉。請你以下面三句話分別作為三段段首主題句，以綠化我們的城市為題，寫一篇文章。

　　With industries and business developing quickly, the number of trees in many big cities has dramatically reduced.

　　Making cities greener has many advantages.

　　Making our cities greener requires nationwide efforts.

　　【范文】

　　Make Our Cities Green

　　With industries and business developing quickly, the number of trees in many big cities has dramatically reduces. Efforts are being made to prevent people from cutting more trees. But a lot of trees are being destroyed by people who have never thought of the importance of green plants.

　　Making cities greener has many advantages. First, it can make our air cleaner. Some researchers have proved that trees can reduce the amount of carbon dioxide in the atmosphere through absorption. Second, it can make our cities more beautiful. With trees and flowers everywhere, living conditions can be improved. Finally, it can produce timber----an effective way to solve the problems of limited supply of natural resources.

　　Making our cities greener requires nationwide efforts. People in every field should not only know about the importance of keeping the quality of urban environment, but also take common action to plant more trees and flowers so as to improve our living conditions.