2009年高中英語條件句表達的六種熱點考查方式

條件句的表達形式有：

1. if如果 

You should call 119 if there's a fire.

If you think that treating a woman well means always getting her permission for things, think again. (06湖南)  

2. unless如果不,除非(多數(shù)情況下與if...not用法相同,兩者都引導條件狀語從句,但unless比if ... not的語氣要強｡

例如：

You will be late ,      you leave immediately.

A. unless   B. until   C. if      D. or

答案A｡句意： 除非你立即走,否則你會遲到的｡該句可轉化為If you don’t leave immediately, you will be late. B､D項填入后句意不對,or表轉折,若用or則句子應為： Leave immediately or you will be late. 再如： 

He is sure to come unless he has some urgent business. = He is sure to come if he hasn’t any urgent business.

注意： 當unless引導的從句的主語與主句的主語相同時,unless后面的主語和動詞有時可省略｡

Unless (he is) in uniform, he doesn’t look like a policeman.除非他穿著制服,否則他看起來不像警察｡

He will not come unless (he is) invited.除非被邀請,否則他是不會來的｡

但在下列情況下要斟酌替換使用： 

1) 當從句是虛擬形式時,只用if ... not,不用unless引導｡例如：

The flowers would have died if you had not watered diligently.

2) 當主句為疑問句時,不用unless,而用if ... not｡例如：

What shall we do if he doesn’t reply to our letter?

3) 當unless引導的從句帶有否定詞時,不能用if ... not代替｡例如：

I’ll go unless no one else goes.

3. as long as只要 

As long as there is life there is hope. 有生命就有希望｡(留得青山在,不怕沒柴燒｡)

I’ll accept any job as / so long as I don’t have to get up early.只要不必早起,任何工作我都可以接受｡ 

4. once作連詞表示“一旦,只要”,引導條件狀語從句｡

Once you understand the rules of the game, you will enjoy it.一旦你了解了游戲的規(guī)則,你就會喜歡它｡

Once he is free, he will play computer games. 只要他有空,他就玩電腦游戲｡

例如：_______environmental damage is done, it takes many years for the ecosystem(生態(tài)系統(tǒng)) to recover.

A. Even if                B. If only

C. While                  D. Once

解析： 答案為D｡even if“即使”,if only “要是……就好了”,while“雖然”, once“一旦”｡句意為“一旦環(huán)境遭到破壞,就要花很多年才能恢復生態(tài)系統(tǒng)”,故D正確｡once作連詞表示“一旦,只要”,引導條件狀語從句｡再如： 

5. 祈使句或名詞短語 + 含有一般將來時或情態(tài)動詞的陳述句

例如：Dress warmly,     you’ll catch cold.

［A］ on the contrary ［B］ or rather            ［C］ or else              ［D］ in no way

［分析］ 本題考查固定句型：“祈使句+or (else) /and you will...”。其中，祈使句相當于if或unless引導的條件狀語從句，并列連詞后面的句子多用將來時表示結果。連詞or (else)（也可以用otherwise）意為“否則”，后面的句子是轉折的結果；連詞and意為“那么，如此一來”，后面的句子是順承的結果。如：Wait a minute and I’ll tell you all about it.（再等一會兒我就會告訴你事情的全部。）Come on, or you will miss the chance.（加油，否則你將失去這個機會。）本題中前后分句是轉折關系，應選［C］or else。 

其他選項都是固定短語，但是表示的邏輯關系均不符合句意。on the contrary意為“（與此）相反”，如：I thought the movie would have been terrible; on the contrary it is very interesting.（我原以為這部電影會很糟糕，結果相反，它很有意思。）or rather意為“更確切地說”，如：I am 1 year older than you, or rather 1 year and 2 months.（我比你大一歲，更確切地說大一歲零兩個月。）in no way意為“決不”，放在句首時，引起句子倒裝，如：In no way can we allow this to continue.（我們決不允許它再繼續(xù)下去。）

［句意］ 穿暖和一些，不然你會感冒的。 

6. provided意為“如果，倘若，只要”，引導條件狀語從句 

You can arrive in Beijing earlier for the meeting     you don’t mind taking the night train.

［A］ provided           ［B］ unless        ［C］ though              ［D］ until

［分析］ provided意為“如果，倘若，只要”，引導條件狀語從句，相當于if，如：The boss will pay the bonus provided（that）the job is completed on time.（如果工作按時完成的話老板將發(fā)獎金。）unless相當于if …not，引導條件狀語從句，意為“如果……不……，非…… 不可，除非”，由于它是具有否定意義的連接詞，因此所引導的從句謂語一般是肯定形式，如：Unless the rain stops，I shall not go out for a walk.（倘若雨不停，我就不出去散步了。）though意為“雖然，盡管；可是，然而”，引導讓步或轉折從句，如：Though she gave no sign, I was sure she had seen me.（盡管她沒有示意，我還是確信她看見了我。）Your suggestion is feasible, though it may be rather costly.（你的建議是可行的，但也許要付出不少代價。）until常和not搭配，引導時間狀語從句，意為“直到……才”，如：He did not leave the house until his father returned.（他直到父親回來才離開房子。）根據(jù)句意，應選［A］provided。

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