1、grammargrammarConditional clausesConditional clauses第1页条件状语从句条件状语从句l l 引导条件状语从句最惯用连词是引导条件状语从句最惯用连词是if,常,常见见if条件状语从句表示在某条件下,某事很条件状语从句表示在某条件下,某事很可能发生可能发生 l lIf youIf you ask ask him him,he he will helpwill help you youl l假如你请他帮忙,他会帮你。假如你请他帮忙,他会帮你。l lIf you If you fail fail in the examin the exam,you y
2、ou will letwill let him him downdownl l假如你考试不及格,你会让他失望。假如你考试不及格,你会让他失望。第2页l l假如你作业做完了就能够回家了。假如你作业做完了就能够回家了。l l If you If you have finishedhave finished the homework the homework,you you can gocan go home.home.第3页1.If 从句从句(普通现在时),(普通现在时),主句主句(普通现在时普通现在时)l l表示科学常识,说明,表示科学常识,说明,经常性动作,倾向经常性动作,倾向 自自动会发生事
3、动会发生事 l l1.If water 1.If water is heatedis heated,it,it turnsturns to steam.to steam.l l2.If people 2.If people dont getdont get enough sleep,their enough sleep,their thinking ability thinking ability is reducedis reduced.l l3.If I 3.If I needneed a haircut,I usually a haircut,I usually gogo to the
4、to the barbers near where I live.barbers near where I live.l l4.People often 4.People often dont godont go out on Sundays if it out on Sundays if it rainsrains.第4页2表示未来可能性,能力,表示未来可能性,能力,允诺,命允诺,命令,要求,请求,提议时,令,要求,请求,提议时,利用利用“主将从现主将从现”标准。标准。l l1.If I 1.If I getget the job,I the job,Ill buyll buy a mobi
5、le phone.a mobile phone.l l2.If my homework 2.If my homework is is difficult,I difficult,Ill askll ask Helen to Helen to help me.help me.l l3.If I 3.If I havehave time this afternoon,I time this afternoon,Ill goll go to the to the barbers to get a haircut.barbers to get a haircut.第5页那么,除了那么,除了if之外,是
6、否还有其它连之外,是否还有其它连词能够引导条件状语从句呢词能够引导条件状语从句呢 l l 回答是必定。不但有,还有很多。这些回答是必定。不但有,还有很多。这些词因为出现频率小,且使用方法较复杂一词因为出现频率小,且使用方法较复杂一些,所以不如些,所以不如if为大家所熟知罢了。下面就为大家所熟知罢了。下面就这些词使用方法做一介绍。这些词使用方法做一介绍。第6页1unless 除非;若不;假如不除非;若不;假如不;除非在除非在时候时候 l l1.You will fail to arrive there in time 1.You will fail to arrive there in time
7、 unless unless you you start earlierstart earlierl l假如你不早点动身,你就不能及时赶到那儿。假如你不早点动身,你就不能及时赶到那儿。2.2.UnlessUnless bad weather stops me bad weather stops me,I go for a I go for a walk every morningwalk every morningl l除非天气不好,我天天早晨都要去散步。除非天气不好,我天天早晨都要去散步。l l3.I wont loan you 3.I wont loan you unlessunless
8、you are in extreme you are in extreme need of moneyneed of moneyl l若不是你急需用钱,我不会借钱给你。若不是你急需用钱,我不会借钱给你。第7页2 2on condition thaton condition that只有在只有在条件下,条件下,以以为条件为条件 l lon condition thaton condition that引导条件从句是主句中事件引导条件从句是主句中事件发生发生前提条件或唯一条件。前提条件或唯一条件。l lI can tell you the truth I can tell you the trut
9、h on condition thaton condition that you you promise to keep a secretpromise to keep a secretl l我能够告诉你真相,条件是你答应保守秘密。我能够告诉你真相,条件是你答应保守秘密。l lYou can pass the custom You can pass the custom on condition thaton condition that we have checked your luggagewe have checked your luggage你能够经过你能够经过海关,但条件是我们得检验
10、完你行李。海关,但条件是我们得检验完你行李。第8页3 3supposing(that)conjsupposing(that)conj假若,倘若假若,倘若 l lsupposingsupposing 引导从句表示一个引导从句表示一个假设条件假设条件。通常在。通常在句首句首 l lSupposingSupposing it rains it rains,shall we continue the shall we continue the sports meetingsports meeting?l l倘若下雨,我们运动会还会继续进行吗?倘若下雨,我们运动会还会继续进行吗?l lSupposing
11、Supposing the stocks of food run out the stocks of food run out,what what shall we doshall we do?l l假若贮备食品都吃光了,我们怎么办呢?假若贮备食品都吃光了,我们怎么办呢?第9页4 4provided that./providing(that)provided that./providing(that)conjconj假若假若 l lprovided/providing provided/providing(thatthat)从句)从句 表示一个表示一个假设条件。假设条件。l lHe will
12、sign the contract He will sign the contract provided(that)provided(that)we offer we offer more favorable termsmore favorable termsl l假如我们提出更优惠条件,他就会在协议上签字。假如我们提出更优惠条件,他就会在协议上签字。l lHe wont be against us in the meeting He wont be against us in the meeting providing providing(that)(that)we ask for his
13、advice in advance we ask for his advice in advancel l假如我们提前征求一下他意见,他就不在会上反假如我们提前征求一下他意见,他就不在会上反对我们。对我们。第10页5.as(so)long as.“5.as(so)long as.“只要只要,就就 ”表示表示 一个前提条件一个前提条件l lYoull succeed Youll succeed as(so)long as(if only)as(so)long as(if only)you try hard.you try hard.l l只要你努力,你就会成功。只要你努力,你就会成功。第11页b
14、ut forbut for +短语,短语,要不是要不是l l6.6.But for the rainBut for the rain,we we should haveshould have a pleasant a pleasant journeyjourneyl l要不是下雨,我们旅行必定很愉快。要不是下雨,我们旅行必定很愉快。l l=If it=If it didnt raindidnt rain,we,we should haveshould have a pleasant a pleasant journey.journey.l lBut for your help,we But f
15、or your help,we should not have should not have finishedfinished the task in time the task in timel l要不是你帮忙,我们必定不能及时完成任务。要不是你帮忙,我们必定不能及时完成任务。l l=If you=If you hadnt helpedhadnt helped us,we us,we should not have should not have finishedfinished the task in time the task in time.第12页Without.+Without.
16、+短语,短语,假如没有假如没有.l l7.7.Without water,there Without water,there would bewould be no life no life on earth at allon earth at all假如没有水,地球上就不假如没有水,地球上就不会有生命。会有生命。l l=If there=If there werewere no water,there no water,there would bewould be no no life on earth at all.life on earth at all.第13页If If+虚拟条件句,
17、虚拟条件句,l l1.If I 1.If I werewere you you,I I would invitewould invite him to the him to the partypartyl l假如我是你,我会邀请他参加聚会。假如我是你,我会邀请他参加聚会。l lI I would have arrivedwould have arrived much earlier if I much earlier if I had had not been caughtnot been caught in the traffic in the trafficl l要不是交通堵塞,我本会来得早一些。要不是交通堵塞,我本会来得早一些。l lIf it If it should beshould be true,it true,it would bewould be silly to silly to argue any longer.argue any longer.第14页