With industris and businss dvloping quickly, th numbr of trs in many big citis has dramatically rducs. fforts ar bing mad to prvnt popl from cutting mor trs. But a lot of trs ar bing dstroyd by popl who hav nvr thought of th importanc of grn plants.Making citis grnr has many advantags. First, it can mak our air clanr. Som rsarchrs hav provd that trs can rduc th amount of carbon dioxid in th atmosphr through absorption. Scond, it can mak our citis mor bautiful. With trs and flowrs vrywhr, living conditions can b improvd. Finally, it can produc timbr----an ffctiv way to solv th problms of limitd supply of natural rsourcs. Making our citis grnr rquirs nationwid fforts. Popl in vry fild should not only know about th importanc of kping th quality of urban nvironmnt, but also tak common action to plant mor trs and flowrs so as to improv our living conditions.