【正文】 表示對過去正在發(fā)生事情的推測。Your mother must have been looking for 。5)推測的否定形式，疑問形式用can’t，couldn’t表示。Mike can’t have found his car，for he came to work by bus this ，因?yàn)樵缟纤亲财噥砩习嗟?。注意：could，might表示推測時不表示時態(tài)，其推測的程度不如can，may。+have+過去分詞1)may(might)have+done (could)have+done ，推測過去時間里可能發(fā)生的事情。Philip may(might)have been hurt seriously in the car 。2)must have+done ，語氣較強(qiáng)，具有“肯定”“諒必”的意思?！狶inda has gone to work，but her bicycle is still here.—She must have gone by )ought to have done sth.／should have done ，而事實(shí)上并沒有做。否定句表示“不該做某事而做了”。He ought not to have thrown the old clothes away.（事實(shí)上已扔了。）ought to 在語氣上比should 要強(qiáng)。4)needn’t have done I dressed very warmly for the trip，but I needn’t have done weather was ，我穿的非常暖和，但我本沒有必要那么去做。天太熱了。5)would like to have done I would like to have read the article，but I was very busy ，但我那時太忙了。 和ought toshould 和ought to 都為“應(yīng)該”的意思，可用于各種人稱?！狾ught he to go?— think he ought ，命令時，語氣由 should（應(yīng)該），had better最好），must（必須）漸強(qiáng)。 better表示“最好”had better 相當(dāng)于一個助動詞，它只有一種形式，它后面要跟動詞原形。had better do had better not do had better have done ，意為“本來最好”。 rather表示“寧愿” would rather do 寧可干某事would rather not do 寧可不干某事 would rather...than...寧愿……而不愿還有would sooner，had rather，had sooner都表示“寧愿”“寧可”的意思。I would rather stay here than go home.=I would stay here rather than go 。1)would like；would like to do=want to 想要，為固定搭配。Would you like to go with me?你想和我一塊兒去嗎？2)Will you...? Would you like...?表示肯定含義的請求勸說時，疑問句 中一般用some，而不是any。Would you like some cake?要蛋糕嗎？3)否定結(jié)構(gòu)中用will，一般不用would，won’t you是一種委婉語氣。Won’t you sit down?你不坐嗎? must和need相同:Yes,...,...needn39。t/don39。t have to may和can could相同:Yes,...may/can/,...mustn39。t/...39。d better not/can39。:Yes,...can/,...can39。:Yes,...,...shouldn39。:Yes,...do/,...won39。t/1）Could I borrow your dictionary?Yes,of course, , course,表示肯定的語氣,允許某人做某事時,用can和 may來表達(dá),：will 與you連用, 連用,）Shall I tell John about it?No,you 39。ve told him 39。t 39。t 39。t 39。t 39。t 不必,39。t 將不,mustn39。t 禁止、39。t ,不必的意思,應(yīng)用needn39。）Don39。t forget to e to my birthday party don39。t won39。t can39。t haven39。t ,表請求、建議、也可作為實(shí)義動詞表“意愿、意志、決心”,本題表示決心,一、need表示“需要”或“必須”，作情態(tài)動詞時，僅用于否定句或疑問句中，在肯定句中一般用must,have to,ought to，或should代替。 I attend the meeting tomorrow?我需要明天參加會議嗎? need not hand in the paper this 。need 是一個情態(tài)動詞，他的用法完全和其他情態(tài)動詞一樣，但 need 還可當(dāng)作實(shí)義動詞使用，這時 need 就象其他動詞一樣，有第三人稱，單復(fù)數(shù)，后面加帶 to 的動詞等特性。 need a bike to go to 。 you need a dictionary? 你需要詞典嗎? needs a 。needn39。t + have + 過去分詞 表示過去做了沒必要做的事情。You needn39。t have taken it 。二、Dare表示“敢”，Dare作情態(tài)動詞時，主要用于疑問句、否定句和條件從句中，一般不用在肯定句中。多用在否定或疑問句中。 little girl dare not speak in 。 you catch the little cat? 你敢抓小貓嗎? dare 除用作情態(tài)動詞外，更多的是當(dāng)實(shí)義動詞使用，用法同實(shí)義動詞一樣，要考慮人稱，單復(fù)數(shù)，時態(tài)等。 you dare to walk in the dark? 你敢黑夜走路嗎？ doesn39。t dare to tell the teacher what happened that 。三、Dare和need常用作實(shí)義動詞，有時態(tài)、人稱和數(shù)的變化，所不同的是，作實(shí)義動詞時，在肯定句中，dare后面通常接帶to的不定式，在否定和疑問句中，dare后面可接帶to或不帶to的不定式。如：I dare to swim across this does not dare(to)39。t you dare(to)touch it!I wondered he dare(to)say needs to finish it this 的被動含義：need，want，require，worth（形容詞）后面接doing，也 可以表示被動：need doing=need to be done Shall用于第一人稱,：What shall we do this evening? 、第三人稱疑問句中,：Shall we begin our lesson? When shall he be able to leave the hospital? 、第三人稱,表示說話人給對方命令、警告、：You shall fail if you don39。t work harder.（警告）He shall have the book when I finish reading.（允諾）He shall be punished.（威脅）