1、情态动词学习六要素一、注意情态动词的推测用法推测性情态动词共有三个，其用法见表 情态动词 含义 适用句型 适用句型 可能，或许 肯定句 Must 一定，必须 肯定句 Can/could 可能，或许 否定句，疑问句 例 1：-Are you coming to Jeffs party?-Im not sure. I _go to the concert instead.(NMET2000)A. mustB. would C. should D. might析：选 D。 Im not sure.的语境表明把握性不大，当然我去参加音乐演奏会的可能性就比较小了，故不用 must应用might例 2：-
2、_the news be true?No, it_be true.A. Can, cant B. May, cantC. May, may not D. Must, mustntu析： 选 A。因为前半句是疑问句，后半句为否定句，两空都不能使用may/might 和 must，应而用 can和cant。二、了解情态动词的完成式用法（一） should /ought to have done本来应做而未做，表达遗憾感情色彩例 1： I told Sally how to get there,but perhaps I _for her.(NMET94)A. had to write it out
3、 B. must have written it outC. should have written it out D. ought to write it out析：选 C。分析语境可知，口头上告知Sally如何去那里是不够的，所以我本应书面告知，却有没书面告知之，显得应使用 should /ought to have written表示遗憾之情。例 2：I was really anxious about you, you_home without a word.(NMET2001)A. mustnt leave B. shouldnt have left C. couldnt have
4、left D. neednt leave 析 : 选 B。由语境可知，我真的为你担心，所以你不应该一句话不说就离开家，但实际上你确实这么做了，显然应填 shouldnt/ought to have left，表示责备。 （二） may/might have done可能已做must have done 一定已做cant have done不可能做例 1： -Where is my pen?- I _it.(NMET88)A. might lose B. wouldnt have lost C. should have lost D. must have lost例 2：The light in his room is still on, so he _ to bed.A. mustnt have gone B. must have goneC. shouldnt have gone D. cant have gone析：选 D。由于他房间里的灯还亮着推测，他不可能已经上床睡觉了，应填 cant have gone 。（三） could have done指本来能做而实际未做，表达遗憾的感情色彩 You could at least have sent five cards.你至少可以寄 5张明信片的。
