一、了解相互间关系
had better(最好), should(应该)与ought to(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had better语气强,ought to语气最强。一般情况下should与ought to可通用。
例1:You had better go there at once. 你最好立即去那里。
例2:You ought to / should work hard.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:You can't imagine that a well-behaved gentleman should be so rude to a lady. 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
had better, should, ought to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
had better, should, ought to用于否定句时,否定词均位于其后,具体形式为:had better not do, shouldn't / should not do, oughtn't to do。
例1:You had better not start at this time. 此时你最好别出发。
例2:He shouldn't be careless in class. 他上课时不应粗心。
例3:She oughtn't to waste time. 她不应该浪费时间。
(二)一般疑问句
had better, should, ought to用于一般疑问句时,分别将had, should, ought提至句首。
例1:Had he better start early at once? 他最好立即出发吗?
例2:Should you do like this? 你应该这么做吗?
例3:Ought he to go there? 他应该去那里吗?
(三)反意疑问句
陈述句
谓语动词含had better, should, ought to时,反意疑问句为:had, should与ought+主格
人称代词或hadn't, shouldn't, oughtn't+主格人称代词。
例1:You had better not go home, had you? 你最好别回家,是吗?
例2:You should study hard,
shouldn't you? 你应该认真学习,是吗?
例3:He oughtn't to speak in class, ought he? 你上课不应该讲话,是吗?
三、 掌握其完成式用法
had better没有完成式,should与ought to完成式意义与用法完全相同。
(一)should/ought to have done 意为本来应做但实际没有做,表达遗憾的感情色彩。
例:There was a lot of fun at yesterday's party. You ________ come, but why didn't you?
A. must have B. should C. need have D. ought to have
析:答案D。 该空含你本来应来但实际未来之意,应填ought to have。
(二)should / oughtn't to have done,意为本来不应做但实际已做,表达遗憾的感情色彩。
例:I was really anxious about you. You ________ home without a word.
A. mustn't leave
B. shouldn't have left
C. couldn't have left
D. needn't leave
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shouldn't have left。
追问求ought to否定句的回答肯定和否定两种回答,是Yes,I ought to.还是Yes,I ought.
追答是Yes,I ought to
追问可是其他改变都只在ought上做变化?