1. 表示推測：情態(tài)動詞＋ be＋表：現(xiàn)在狀態(tài)

                        be doing：現(xiàn)在動作

                        have done：過去

may/might have done：本可以干某事

can/could have done：本能夠干某事

should/ought to have done：本應該干某事

needn’t have done：本不必干某事

would/should like/love to have done：過去本想干某事

had better have done：當初最好干某事

would rather have done：當然真該干某事

注：情態(tài)動詞表推測時，其反意疑問句，應把情態(tài)動詞變?yōu)椴皇峭茰y的來考慮。

2. 幾個情態(tài)動詞的辨析與特殊用法：

（1）can/could用于肯定句中表“可以”，或“能夠”（強調(diào)與生俱來的能力）；be able to強調(diào)過去設法完成的某一具體的動作。

（2）used to表示過去常常干某事，暗示“現(xiàn)在不干了”，以及表示過去一直存在的狀態(tài)；would表示過去常常干某事，但不涉及現(xiàn)在的情況，還可以表示過去一直煩人的事情。

（3）need/dare作為實義動詞時，應用need/dare to do; 作為情態(tài)動詞時，一般不用于肯定句中。

（5）will可以表示意愿或必然趨勢。

If he won’t help us, all our plans will be ruined.

The window won’t open.

3. 虛擬語氣應用于如下結構中：

（1）一種定語從句：It’s time that+did

（2）兩種目的狀語從句：

so that/in order that+ can/may/could/might +do

（3）三種隨時變化句：

①     wish        現(xiàn)在→did/were

      if only   ＋  過去→had done

  as if/though       將來→could/would do

② would rather ＋ 現(xiàn)在/將來→did/were

                 過去→had done

③ 現(xiàn)在：if+did/were, would+ do

   過去：if+had done, would+ have done

   將來：     did

          if+  were to do, would+ do

              should do

注意：除了由if引導的虛擬條件句外，還有倒裝條件句，即把were、had或should提前；混合時間句，虛實錯綜句，以及含蓄條件句，即由or, otherwise, with, without, but for來引導的。

（4）四種名詞性從句：

①當表語是important, natural, necessary, possible, strange, arranged, decided, demanded, ordered, requested, suggested, surprising, a pity, no woder時，主語從句要用虛擬語氣。例：

It’s important that we (should) help each other.

②動詞一堅持(insist)，兩命令(command, order)，三建議(advise, propose, suggest)，四要求(ask, demand, request, require)后的賓語從句要用虛擬語氣。例：

He insisted that he (should) be sent to the West.

注：insist(堅持說), suggest(暗示，表明)時，從句應用陳述語氣。如：

Her pale face suggested that she was ill.

③idea, plan以及表示“堅持，命令，建議，要求”等動詞的同源名詞作主語時，表語從句用虛擬語氣。例：

My suggestion is that we (should) hold a class meeting.

④idea, plan以及表示“堅持，命令，建議，要求”等動詞的同源名詞后的同位語從句要用虛擬語氣。例：

The office gave an order that his soldiers fight back bravely.

巧用上下文語境。①注意上下文的信息提示：信息提示出現(xiàn)在前文時，可以根據(jù)前文的信息提示確定答案；信息提示出現(xiàn)在后文時，我們應該先把此空暫時擱置，在理解了后文的基礎上，再確定答案。②通讀全文，利用復現(xiàn)詞語：完形填空試題中，一些詞語會重復出現(xiàn)在語篇之中。詞匯復現(xiàn)使得語篇中的句子相互銜接，從而構成一個完整的、有機的意義整體。把握這些反復出現(xiàn)的詞語，有助于我們確定正確答案。

例1：Reading is a way of learning English without classes or a teacher. It helps develop learners’ independence. And while reading graded readers, learners don’t have to run a____ because the language is at their level.

A. dictionary       B. teacher            C. student            D. recorder

[分析]because在此引導一個原因狀語從句，因為讀物中使用的語言符合讀者的語言水平，讀者當然不必求助于詞典。

例2：All of a sudden I started to feel rather__1__. She wondered why I was looking for this sort of__2___. I felt even more hopeless when she told me that it would be difficult to get a job without experience.

1. A. encouraged           B. dissatisfied      C. hopeless                   D. pleased

2. A. place                     B. job                  C. advice             D. help

[分析]文章講到作者去應聘工作，既沒有經(jīng)驗又信心，心里感到十分不踏實。從下文中的“I felt even more hopeless”可知第1題填“hopeless”，暗示作者那種無望的心情。而“it would be difficult to get a job without experience”則呼應了第2題，故選job。

例3：Years ago in Scotland, the Clark family had a dream. Clark and his wife worked and____, making plans for their nine children and themselves to travel to  2(America) . It had taken years, but they had   3(finally)  saved enough money and had gotten passports and reservations for the whole family on a new liner t the United States.

A. spent               B. counted           C. saved              D. played

[分析]分析上面一段文字可知Clark夫婦存錢的目的是讓一家人出去旅游。根據(jù)文中“but they had  3(finally)  saved enough money”可知第1題答案為C項。