一、用“情態(tài)動詞＋have ＋done”結(jié)構(gòu)表示對過去動作的推測,試題中常用過去時態(tài)或過去的時間狀語給以暗示.情態(tài)動詞的這一用法可以用 “對立統(tǒng)一”來概括.
1．當(dāng)試題的前句和后句在動作和意義上相互補(bǔ)充說明,且整個句意在動作和時間上是一個整體時,我們可用“統(tǒng)一”關(guān)系來解決這樣的試題.常見的結(jié)構(gòu)有：
must have done： 表示對過去動作的肯定推測,常譯作“一定做了……”,只能用于肯定句中.其否定形式為can‘t／couldn‘t have done 疑問式為Can／Could...have done?.
could ／might have done：表示對過去發(fā)生的動作的可能性推測,常譯作“可能做了……”.如：
1) Sorry I‘m late． I ＿＿＿＿＿ have turned off the alarm clock and gone back to sleep again．
A． might B． should C． can D． will
該題前句說明了結(jié)果,后句接著說出了產(chǎn)生這種結(jié)果的可能性,對前句進(jìn)行補(bǔ)充說明.分析選項(xiàng)可知本題應(yīng)選A.
2) My sister met him at the Grand Theater yesterday afternoon, so he ＿＿＿＿ your lecture．
A．couldn‘t have attended
B．needn‘t have attended
C．mustn‘t have attended
D．shouldn‘t have attended
該題前句敘說一個客觀事實(shí),后句對前句進(jìn)行補(bǔ)充說明,分析選項(xiàng)可知C是錯誤的; 而B、D兩項(xiàng)不符合題意.故本題選A.又如：
Jack ＿＿＿＿ yet, otherwise he would have telephoned me．
A．mustn‘t have arrived
B．shouldn‘t have arrived
C．can‘t have arrived
D．need not have arrived （C）
2．當(dāng)試題的前后句在動作和意義上構(gòu)成轉(zhuǎn)折關(guān)系時,常借助“but, however, instead”等詞來表示過去的動作與客觀事實(shí)不符,這時我們就可以用“對立”關(guān)系來解決這樣的試題.這種結(jié)構(gòu)常見的有：
should have done ／ ought to have done：表示過去本應(yīng)該做某事而實(shí)際上沒有做.
should not have done ／ ought not to have done：表示過去本不應(yīng)該做某事但事實(shí)上卻做了.
need have done：表示過去本來有必要去做某事,但事實(shí)上沒有做.
need not have done：表示過去本來沒有必要做某事,但事實(shí)上卻做了.如：
3) 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
分析該題前后句之間的關(guān)系和語氣可知,事實(shí)上是 “本不應(yīng)該離家出走卻走了”,故本題選B.
4) I told Sally how to get here, but perhaps I ＿＿＿＿＿ for her．
A．had to write it out
B．must have written it out
C．should have written it out
D．ought to write it out
由句中的連詞but可知前后句之間是對立關(guān)系,分析題意可知本題應(yīng)選C.
二、考查情態(tài)動詞基本用法之間的比較和辨析.最近幾年試題中常借助具體的語境來考查考生對那些最常見的情態(tài)動詞的基本用法的理解和把握,因此在做這樣的試題時應(yīng)認(rèn)真分析語境中所含的實(shí)際意義,并結(jié)合情態(tài)動詞的基本含義和用法做出正確的選擇.
5) —Is John coming by train?
—He should, but he ＿＿＿＿＿＿ not． He likes driving his car．
A．must B．can C．need D．may
mustn‘t 表示“禁止、不準(zhǔn)”；cannot 表示“不可能”；need not 表示“不必要”；may not 表示“可能不”.分析語境可知本題應(yīng)選D.
6) —I hear you‘ve got a set of valuable Australian coins．＿＿＿ I have a look?
—Yes, certainly．
A．Do B．May C． Shall D．Should
分析語境可知這是在征求對方的許可,may表示“答應(yīng)、可以”,語氣比較委婉 shall常用于第一、三人稱作主語的疑問句中,表示征求對方意見和指示,假如此空用shall,則意為“要（我）看一下嗎?”,不符合上下文意思.故本題選B.
7) Mr Bush is on time for everything． How ＿＿＿＿ it be that he was late for the opening ceremony?
A．can B．should C．may D．must
must be 表示肯定的猜測,只能用于肯定句中,由題意可知本題應(yīng)選A.
8) —Are you coming to Jeff‘s party?
—I‘m not sure． I ＿＿＿＿ go to the concert instead．
A．must B．would C．should D．might
由題意和下句中的 “I‘m not sure” 可知這段對話中存在一種可能性推測,might可以用來表示一種比較委婉的可能性判定,故本題選D.又如：
I should have been there, but I ＿＿＿＿＿ not find the time．
A．would B．could C．might D．should
分析題意可知第二個分句表示過去的某種能力；C 項(xiàng)只表示語氣上的可能性,與題意不符.故本題選B.
9) Johnny, you ＿＿＿＿ play with the knife, you ＿＿＿＿ hurt yourself．
A．won‘t; can‘t B．mustn‘t; may
C．shouldn‘t; must D．can‘t; shouldn‘t
mustn‘t 表示“不可以；禁止”,分析題意可知第二個空表示某種可能性,故本題選B.
10) —Will you stay for lunch
—Sorry, ＿＿＿＿＿＿． My brother is coming to see me．
A．I mustn‘t B．I can‘t C．I needn‘t D．I won‘t
分析題意可知因?yàn)椤拔业艿芤獊砜次摇?所以“不能留下”,因此對別人的邀請或要求應(yīng)給予禮貌的拒絕.A 項(xiàng)表示“禁止”；C項(xiàng)表示“不必要”；而D項(xiàng)表示“不會”,均不符合題意.故本題選B.又如：
—Could I borrow your dictionary?
—Yes, of course you ＿＿＿＿＿．
A．might B．will C．can D．should
11)—When can I come for the photos? I need them tomorrow afternoon．
—They ＿＿＿＿＿ be ready by 1200．
A．can B．should C．might D．need
該題考查情態(tài)動詞should的基本含義,分析句意可知本題應(yīng)選B.又如：
The old man is always hunting the lions, so terrible things ＿＿＿＿ happen to him．（上海‘96）
A．might B．would C．should D． could 烠
12)The fire spread through the hotel very quickly but everyone ＿＿＿＿ get out．
A．had to B．would C．could D．was able to
該題考查了could和be able to的區(qū)別,二者都可表示過去時間的能力,但假如表示過去成功地做了某事只能使用was ／ were able to do,故本題選D.
13)—Shall I tell John about it?
—No, you ＿＿＿．I‘ve told him already．
A．needn‘t B．wouldn‘t C．mustn‘t D．shouldn‘t
情態(tài)動詞shall在試題中表示征詢對方意見或請求指示.答句暗示 “沒有必要了”,故本題選
A