摘要： as 改为if或 though 书面表达 Dear Editor, We are astonished to learn from a CCTV ad that each year, about 45 billion pairs of disposable chopsticks are produced in our country. 6 million big trees have to be cut down. What shocking facts! Trees play an important part in keeping a good environment. The ecological value of a tree is 9 times that of the chopsticks made from that tree. The chopstick producers may make some money, but they have destroyed a lot of forest resources at the same time. Moreover, when people throw away or burn the used chopsticks, the environment is badly polluted. Our government should take measures to limit or stop the production of disposable chopsticks in order to protect the forest resources and our environment. Yours sincerely Li Hua

网址：http://m.1010jiajiao.com/timu3_id_3159726[举报]