except,besides,exceptfor用法的关联和区别1.作介词用法时,这三个词都有"除…之外"的含义,但except常与do/does/did/have/has/hadnothing等词形成搭配用法,或者与全部肯定词all、everything、ev?eryone等连用,或者与全部否定词nothing、nobody等连用,因此except加宾语作介词"除…之外"时常表示从整体中剔除一部分;而besides作"除…之外"时则表示"另外附加"的含义,相当于"inadditionto"。试比较下列例句:1)HedidnothingexceptwatchTVyesterday.2)Hesaidnothingexcepttosmilejustnow.3)AllthestudentstookatripexceptTomyesterday.4)Weneed3morepersonstofinishthejobbesides/inadditiontoustwo.2.作介词用法时的except后可接多种情况的介词短语。在这种情况下,except后的介词是不可省去的,except加介词的实际作用就相当于连词加相关的从句。例如:1)Theweatherisfinetodayexceptinthenorthwest.此句相当于:Theweatherisfinetodayexceptthatitisinthenorthwest.2)Hismothernevertakesanyexerciseexceptonthedancefloor.此句相当于:Hismothernevertakesanyexerciseexceptthatshehasadanceonthefloor.需要强调的是except与exceptfor的用法区别:1)Except后排除的内容与主语往往是同一类的,而exceptfor后所排除的内容与主语往往不是同一类的。例如,试比较:Allthebuildingsareexcellentexceptthisone.Allthebuildingsareexcellentexceptfortheirlocation或者Allthebuildingsareexcellentexceptthattheplaceonwhichthebuid?ingsarebuiltisnotgood.2)当except用在句首时往往改用exceptfor。例如:Therewasnosinglepersoninthedarkstreetthatnightexceptapolicemanonhisduty.此句相当于:Exceptforapolicemanonhisduty,therewasnosinglepersoninthedarkstreetthatnight.3.相当于连词用法的except与相当于连词用法的besides的区别仍然保持它们作介词用法的含义。试比较下列例句:1)Tomisagoodstudentex?ceptthatheiscareless.此句相当于:Tomisagoodstudentexceptforhiscarelessness.2)Tomseldomcomeslatetoschoolexceptwhenitrainshard.此句相当于:Tomseldomcomeslatetoschoolexceptonaheavilyrainyday.