hadbetter,should,oughtto用法辨析hadbetter,should,oughtto是重要的情态动词，也是高考重要考点，学习时应注意下列几点：一、了解相互间关系hadbetter(最好),should(应该)与oughtto（应该）均为提建议、阐述观点的情态动词，其后接动词原形。should比hadbetter语气强，oughtto语气最强。一般情况下should与oughtto可通用。例1：Youhadbettergothereatonce.你最好立即去那里。例2：Yououghtto/shouldworkhard.你应该努力工作。值得注意的是：should还有竟然之意，表出乎意料。例：Youcantimaginethatawell-behavedgentlemanshouldbesorudetoalady.你真是难以想象这么一个有风度的先生对一个女子是如此之粗鲁。二、掌握句型变换方法hadbetter,should,oughtto作为情态动词，各种句型变换均在自身形式上作变化。（一）否定句hadbetter,should,oughtto用于否定句时，否定词均位于其后，具体形式为：hadbetternotdo,shouldnt/shouldnotdo,oughtnttodo。例1：Youhadbetternotstartatthistime.此时你最好别出发。例2：Heshouldntbecarelessinclass.他上课时不应粗心。例3：Sheoughtnttowastetime.她不应该浪费时间。（二）一般疑问句hadbetter,should,oughtto用于一般疑问句时，分别将had,should,ought提至句首。例1：Hadhebetterstartearlyatonce?他最好立即出发吗？例2：Shouldyoudolikethis?你应该这么做吗？例3：Oughthetogothere?他应该去那里吗？（三）反意疑问句陈述句谓语动词含hadbetter,should,oughtto时，反意疑问句为：had,should与ought+主格人称代词或hadnt,shouldnt,oughtnt+主格人称代词。例1：Youhadbetternotgohome,hadyou?你最好别回家，是吗？例2：Youshouldstudyhard,shouldntyou?你应该认真学习，是吗？例3：Heoughtnttospeakinclass,oughthe?你上课不应该讲话，是吗？三、掌握其完成式用法hadbetter没有完成式，should与oughtto完成式意义与用法完全相同。（一）should/oughttohavedone意为本来应做但实际没有做，表达遗憾的感情色彩。例：Therewasalotoffunatyesterdaysparty.You_come,butwhydidntyou?A.musthaveB.shouldC.needhaveD.oughttohave析：答案D。该空含你本来应来但实际未来之意，应填oughttohave。（二）should/oughtnttohavedone，意为本来不应做但实际已做，表达遗憾的感情色彩。例：Iwasreallyanxiousaboutyou.You_homewithoutaword.A.mustntleaveB.shouldnthaveleftC.couldnthaveleftD.needntleave析：答案B。该空含你本不应该一句话不说就离开家但实际已这么做之意，所以应填shouldnthaveleft。单位：湖北省荆门姓名：李国E_mail：liguo619sina.com