one用作不定代词时,表示泛指,它用来承接前面已出现过的同类可数名词,指同一类中的一个;承接前面出现过的同一个事物时,用it。that用以代替名词,避免重复。指同一种事物,常用“thatof...”的形式。1.IdliketobuyFatherapresentwiththeremaining25dollars,thatisnottooexpensivebutuseful.A.whichB.itC.oneD.theone2.Therearemorethanathousandnewbusesinthecity,andyoudontoftenseethatisempty.A.oneB.thatC.itD.theone3.(NMET2004Ⅲ)Weneededanewcupboardforthekitchen.SoPetermadefromsomewoodwehad.A.itB.oneC.himselfD.another4.Johndidntdoanythingatalltoappl...