【正文】
60。 smallest air in Beijing is getting much _____ now than a few years ago.A. clean B. cleaner C. cleanest D. the cleanest6. Mobile phones are very popular now and they are _____ than before. A. cheap B. cheaper C. cheapest D. the cheapest7 Which is _____ , a bicycle or a puter?A. expensive expensive most expensive8. The Yellow River is one of ______rivers in China A long B longer C the longest is the second _______student in our class. A. tall B. taller C. tallest3