语法的问题,是单数时候就用year's,s在'的前面：oneyear'stime,一年的时间. 　　当你说很多年的时候,复数years,因为语法上不想让你写成years's,所以就写成years'time:4years'time,4年的时间. 　　举例： 　　Apostrophesareusedintimeexpressions(e.g.,threeyears'experience,twodays'pay,oneday'stime).Thesearealsoknownastemporalexpressions. 　　Inatemporalexpression,theapostropheispositionedbeforethesforsingleunitsoftimeandafterformultipleunitsoftime.Forexample: 　　Ineverdidaday'sworkinmylife.Itwasallfun.(ThomasA.Edison) 　　(Asthisisoneday,theapostrophegoesbeforethes.) 　　Alanwasgiventwodays'notice. 　　(Asthisistwodays,theapostrophegoesafterthes.) 　　Thatistheequivalentofoneyear'spay. 　　(Asthisisoneyear,theapostrophegoesbeforethes.)