虛擬條件句難點(diǎn)巧掌握

李　芹

虛擬語氣作為高考難點(diǎn)一直讓許多學(xué)生頭痛不已,非真實(shí)條件句中虛擬語氣的考察更是重點(diǎn).許多語法書上對虛擬的講解總是涉及時態(tài),筆者認(rèn)為這極不利于學(xué)生對此知識點(diǎn)的理解與運(yùn)用. 筆者在教學(xué)實(shí)踐作了一些嘗試，起到了不錯的效果。

一、拋開時態(tài)學(xué)虛擬

張道真實(shí)用英語語法對虛擬語氣的定義如下: 在表示一種純?nèi)患傧氲那闆r或主觀愿望時,動詞需用一種特殊形式,成為虛擬語氣. 時態(tài)與時間有密切關(guān)系,而虛擬語氣實(shí)際是對真實(shí)情況的假設(shè),因此其表達(dá)方式必須與正常時態(tài)的表達(dá)有區(qū)別.因此,拋開時態(tài),把其作為一種特殊表達(dá)方式來理解更容易掌握其規(guī)則.如下表中，用had done 結(jié)構(gòu)表示對過去事實(shí)的虛擬表達(dá)，而不用過去完成時這一概念。因此，在學(xué)習(xí)虛擬語氣時，牢記三個時間段：過去，現(xiàn)在和將來。

以下句為例：She would have said more if he _______(walk) away. 從would have said可看出整個句子時間為過去，因此，按照規(guī)則，空格處應(yīng)為had done結(jié)構(gòu)，再結(jié)合句意，應(yīng)為否定，最終正確答案had not walked 就表達(dá)出來了。

二、善于發(fā)現(xiàn)含蓄的條件

許多同學(xué)誤以為虛擬條件只有if可以引導(dǎo)，其實(shí)不然。

1. without, but for 可引導(dǎo)相當(dāng)于的if條件。例：

But for your help, I couldnt have succeeded.等于If you hadnt helped me, I couldnt have succeeded.

2. or, otherwise 相當(dāng)于if條件。例：

He hesitated for a moment before kicking the ball, otherwise he would have scored a goal. 此題中，otherwise 就等于if he hadnt hesitated.

3. 真實(shí)情況暗含的虛擬條件

虛擬語氣的表達(dá)十分靈活，學(xué)生要善于發(fā)現(xiàn)真實(shí)情況下暗含的言外之意。同一個句子中，既有虛擬語氣，又有陳述語氣。例：

I would go to the concert but I have no time. 從I have no time 可知其言外之意if I had time, I would go to the concert..

4. 從句也可用if it were not for /if it had not been for（若不是）來構(gòu)成謂語。

If it were not for your help, we would be in serious trouble.

If it had not been for your help , we would have been in serious trouble.

三、倒裝問題的解決

虛擬語氣中倒裝問題一直是高考熱點(diǎn)，也是學(xué)生易錯的題型，實(shí)際上，既然可以倒裝，就可以不倒裝，許多同學(xué)更習(xí)慣讀不用倒裝的句子，即用陳述語序表達(dá)的句子。例：

Should it rain, I would stay at home tomorrow.此題中should一詞令許多同學(xué)出錯，而在下句中 If it should rain, I would stay at home tomorrow. 卻很少有同學(xué)出錯。

再如：______ I in your position, I would go.先變?yōu)?If I were in your position, I would go。再進(jìn)行倒裝，就容易多了。因此，看到倒裝題時，先變?yōu)殛愂鼍洹?/p>

四、虛擬還是不虛擬

有時可以用虛擬語氣，也可以不用虛擬語氣，兩種情況有時同時考察到。主句的謂語有時可用祈使語氣，或用陳述語氣。例：

If it should rain tomorrow, we would not go shopping. 也可以用下句表達(dá)

If it rains tomorrow, we will not go shopping.

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