Ought-to的用法

Oughtto的用法ought意为“应该”，是情态动词，没有人称和数的变化，后接动词不定式。一、oughtto具体用法如下：1.(表示义务、责任等)应当,应该Yououghttoworkharderthanthat.2.(表示劝告、建议等)应该,该Youdon'tlookwell.Yououghttogotoseethedoctor.3.(表示猜测、期望)总应该，理应Itoughttobeafinedaytomorrowmorning.4.“oughtto+have+过去分词”表示过去应做某事而实际未做Yououghttohavetoldmethat(butyoudidn't).这时oughtto和should可以互换使用。二、oughtto的否定式和疑问式1.oughtto的否定形式是ought后直接加not构成，其否定形式可缩写为oughtn't。Oneoughtnot(oughtn't)tocrossthestreetagainsttheredlight.2.oughtto的疑问式是将ought提到句首构成。—Oughtwetodoitatonce?—Yes,yououghtto.在反意疑问句里，下面两种形式都可以：Heoughttobeherenow,shouldn't(oughtn't)he?三、should与oughtto表示“应该”时的区别：should表示自己的主观看法，而oughtto语气重，含有“按道理应该……之意”，如要反映客观情况或涉及法律义务和规定时一般用oughtto。Youshouldhelpthemwiththeirstudy.Youarehisfather.Yououghttohelphimtogetagoodeducation.