语法口诀--情态动词

情态动词1.情态动词概述情动人称和数无变化，咱就不能单用它；后接动词原形才合法情态动词有can(could),may(might),must,haveto,shall(should),will(would),need,dare(dared),oughtto.2.表示推测的情态动词a)情动表推测(might,may,could,can,should,oughtto,would,will,must);肯定句不能can；否定句mustn·t须让贤；疑问句can，could身手大显。Shecan`tbeserious.Canhehavereturnhome?Icanoperatethemachinenow.Youcanstoptohavearest.Beingrichisgood,butitcancausetroublesometimes.Yourfriendscanlietoyou.Neverbelievethemallthetime.ThemanspeakingChinesemustbefromChina.Thesighmeansyoumustn`tsmokehere.Wherecouldthemissingchildbenow?b)推测现在或将来用“情动+动原”，“情态+完成”推测过去特常见Thescientistmuststayupthewholenightforthisexperiment.Theymusthavewonthefamefortheyweresoexcited.3.表示意愿的情态动词a)情动表示意愿（shall，should，will，would）；shall用于二三人称，表说话人的意愿；will，would表主语的意愿。TellhimIpromiseheshallhavethebooknextweek.Iwilldomybesttohelpyou.b)疑问句中征求意见：shall与一、三人称会面；will，would与第二人称有缘ShallI/heclosethewindow?Willyougotovisitthemuseumwithmetomorrow?c)Will，would表示意志、意愿和习惯Wewillfightonuntilfinalvictorycomes.HewillsitforhourswatchingTV.4.情态动词的基本用法a)Cancould表示能力，允许和有把握的推断b)May,might表允许、祝愿，表推测语气轻如棉c)Must表必须、必要，表推测预期重如山d)Shall用于一三人称征求意见；用于二三人称表说话人的命令、允诺、威胁或警告也常见e)Should=oughtto表可能、建议、命令或劝告。f)Will，would表意志、意愿和习惯；用于第二人称疑问句征求意见；用于二三人称表推测也常见。g)Need，dare兼作实动和情动h)Need作情动，在疑问或否定中显神通i)Dare作情动，只“敢于”用在疑问、否定或条件句中j)Dare作实动，后接to句子才通5.情态动词+完成时的用法6.情态动词语气的强弱7.would和usedto（do）的区别8.must和haveto的区别9.其它