B didn't have/need to do意指不一定非干某事,而通常也并没有这样做:
I didn't have to translate it for him for he understands Dutch.
我用不着替他翻译,因为他懂荷兰语。
I didn't have to cut the grass myself.My brother did it.
我用不着自己修剪草坪。我的兄弟修剪过了。(无义务,而且无行动)有些人的确把didn't have to/didn't need to用于表示已完成的动作,这时 have或 need都要加以重读:You didn't 'have to give him my name通常意味着没有必要告诉他我的姓名,但是你却告诉了他。但当一个不必要的动作实际已完成了时,还是用needn't have+过去分词为好:
You needn't have given him my name.
你本来没必要把我的姓名告诉他的。
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[Amber demo]
154 needn't,could和should+完成式
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A needn't+完成式常常和could+完成式结合使用。这种用法最好通过例句来说明:
—I wanted a copy of the letter,so I typed it twice.
—You needn't have typed it twice.You could have used a carbon.
—我需要那封信的副本,所以我打了两遍字。
—你没必要打两遍。你当时本可以用复写纸打。
—I walked up six flights of stairs.
—You needn't have walked up;you could have taken the lift.
—我爬了六层楼梯。
—你没必要走着上去;你本来可以乘电梯的。
—She stood in a queue to get an Underground ticket.
—But she needn't have stood in a queue.She could have got a ticket from the machine.
—她排队买一张地铁车票。
—可她本来不需要排队。她本可以在售票机那儿买票。
B needn’t have和 should have的比较
should或ought to在以上A的例句中都可以代替need或could:
She shouldn't have stood in a queue.She should have got tickets from the machine.
她本来就不该去排队。她应当在售票机那儿买票。
但这里存在着含义上的差别:
She shouldn't have stood in a queue.
她本来就不该去排队。(她排队是错误的或愚蠢的。)
She needn't have stood in a queue.
她本不必去排队。(这样做是不必要的,但她却排了队。)
shouldn't have(done)有批评之意。
needn't have(done)不含有批评之意。
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[Amber demo]
155 need意指require(需要)
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如第149节所示,need可以像普通动词那样变化。此时它有
通常的各种规则的变化形式,但没有进行式。
need可以和带to的不定式连用,或者和作宾语的名词/代词连用:
I need to know the exact size.
我需要知道确切的尺寸。
How much money do you need?I need £
5.你需要多少钱?我需要五英镑。
need可以和不定式的被动式或动名词连用
Your hair needs to be cut/needs cutting.
你需要理发了。
The windows need to be washed/need washing.
这些窗户需要擦洗了。
这里可以用want+动名词代替:
Your hair wants cutting.
你需要理发了。
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[Amber demo]
第十五章must,have,will和should表示推断和假设?
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[Amber demo]
156 must表示推断
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A 各种形式
现在时
must+现在式:
He must live here.
他一定是住在这里。
或must+进行式:
He must be living here.
(译文同上。)
过去时
must+完成式:
He must have lived here.
他一定在这里住过。
或 must+ 完成进行式:
He must have been living here.
他当时一定住在这里的。
注意 must的各种过去式表示推断和 had to相当于 must表示义务的区别。
must不能用于表示否定的推断(参见第159节),一般也不用于疑问式,除非是对含有must的推断句提问:
—There is a lot of noise from upstairs.It must be Tom.
—Why must it be Tom?Other people use that flat.
—楼上喧闹的声音很大。一定是汤姆弄的。
—为什么一定是汤姆呢?那套房子里也有别人。
B 例句
He has a house in London and another in Paris,so he must be rich.
他在伦敦有一栋房子,在巴黎又有一栋房子,可知他一定有钱。
—I've had no sleep for 48 hours.
—You must be exhausted.
—我已经48小时没睡觉了。
—你一定筋疲力尽了。
He develops his own films.That must save him a lot of money.
他自己冲洗照片。那样肯定为他节省了很多钱。
I keep meeting him on the bus.He must live/must be living near by.
我接连在公共汽车上碰到他。他一定就住在附近。
The police are stopping all cars.They must be looking for the escapedprisoner.
警察命令每一辆车都停下来(接受检查)。他们一定是在查找逃犯。—What explosion?I didn't hear any.
—You must have heard it!The whole town heard it!
—什么爆炸声?我一点也没听见。
—你一定听见了!全城人都听见了!
He must have taken sleeping pills last night.He didn't wake up till lunch time.
他昨晚一定吃了安眠药。他一直到吃中午饭的时候才醒来。
—I waited under the clock!
—So did I,but I didn't see you!We must have been waiting under differ- ent clocks.
—我在大钟底下等的!
—我也是,可我没见到你!一定是在两个不同的钟底下等的。
—It was a head-on collision,but the drivers weren't hurt.
—They must have been wearing their seat belts.
—这次车祸中肇事车辆迎头相撞,但两个驾驶员都没伤着。
—他们肯定系了安全带了。
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[Amber demo]
157 must与may/might的比较
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它们之间的差别最好通过实例来了解:
(a)设想一个钥匙环上有三把钥匙,而且知道其中一把钥匙是开地下室的门的。