(C)9. the end of last month,we had already learned five units of the book. A.During B.At C.By D.Over D )10.You must use your spare time well,or you will end up nothing. A.does B.do C.to do D.doing 导航页导航页 ( ) 9. the end of last month, we had already learned five units of the book. A.During B.At C.By D.Over ( )10. You must use your spare time well, or you will end up nothing. A. does B. do C. to do D. doing C D