牛津高中英語M9語法狀語從句教案

第5講:狀語從句

學(xué)生姓名年級(jí)高三授課教師王老師備課時(shí)間

教學(xué)

狀語從句

目標(biāo)

重、難

考點(diǎn)

教學(xué)內(nèi)容

狀語從句

一、定義

在句中作狀語的從句是狀語從句，修飾主句中的動(dòng)詞、形容詞或副詞等。狀語從句由從屬連詞引導(dǎo)，

從屬連詞在句中不充當(dāng)句子成分，只起連接作用，狀語從句放在句首時(shí)，要用逗號(hào)，放在句尾時(shí)不

用。

二、分類

根據(jù)意義上的不同，狀語從句可分為：①時(shí)間狀語從句②地點(diǎn)狀語從句③原因狀語從句④目的狀語

從句⑤條件狀語從句⑥結(jié)果狀語從句⑦讓步狀語從句⑧方式狀語從句⑨比較狀語從句

三、時(shí)間狀語從句

(一)引導(dǎo)時(shí)間狀語從句的連詞有：as,when(whenever),before,after,assoonas,until(till),

since,everytime,once.

(二)、“as”as,when,while都有“當(dāng)……的時(shí)候”，可以互用

Whenshewasachild.

Whileshewasachild.SheLivedinParis.

Asshewasachild.

as有“一邊---一邊”的意思

Hesangashewalked.

“when”

Whentheclockstrucktwelve,allthelightswentout.

Iwassleepingwhenshecamein.動(dòng)補(bǔ)

Whenwearrivedatthestation,thetrainhadleft.

“while”主、從句動(dòng)作或狀態(tài)同時(shí)發(fā)生。用while引導(dǎo)的從句用延續(xù)性動(dòng)詞，常表示較長(zhǎng)的時(shí)間

或一個(gè)過程。

Whilewewerehavingsupper,allthelightswentout.

Pleasekeepquietwhileothersarestudying.

WhileIwaswritingletterslastnight,hewaswatchingTV.

when,while并列連問。when和while都可用作并列連問，連接并列分句。When表示“就在...

的時(shí)候”，while意反而，可是，表示轉(zhuǎn)折。OneeveningBeethovenwaswalkinginastreet,

whenhesuddenlystoppedoutsidealittlehouse.

并列連詞引導(dǎo)并列句，意思是就在那時(shí)。

（三）、主句是一般將來時(shí)，時(shí)間狀語從句用一般現(xiàn)在時(shí)表將來，主句是過去將來時(shí)，從句用一般

過去時(shí)表示過去將來時(shí)，主句是一般過去時(shí)，從句用一般過去時(shí)。

1.r11callyouwhenIgetthere.

2.Theysaidtheywouldleavewhentheygotthenew.

3.Theyleftassoonastheygotthenew.

Whenever無論什么時(shí)候，隨時(shí)

1.Wheneversomeonethrowsinsomerubbish,thetruckproducesapieceofmusic.

每當(dāng)有人扔進(jìn)一些垃圾時(shí)，它（汽車）就放一段音樂。

2.Wheneverwe'reintrouble,theywillhelpus.

3.Igotothetheatre,wheneverIamfree.

4.Comeandseemewheneveryouwantto.你隨時(shí)來看我。

till和until（表示"直到……”）句首多用until

1、在肯定句中表示“直到……為止”，主句謂語動(dòng)詞要用延續(xù)性動(dòng)詞。

Iwaswaitinguntil/tillhearrived.

2、在否定句中表示“直到……才”主句謂語動(dòng)詞常用終止性動(dòng)詞，這時(shí)until和till常被before

替換。

Ididn，tleavetill/untilshecameback.

since:主句用完成時(shí)，從句用一般過去時(shí)，since引導(dǎo)的從句間或可用現(xiàn)在完成時(shí)。

ItistwoyearssinceIhavestudiedEnglish.

1.Wehaveknowneachothersincewewerechildren.

2.Wehavebeenfriends（eversince）sincewemetatschool.

3.Itis...（一段時(shí)間）+since+一般過去時(shí)態(tài)句子。

Itistwoyearssincemysistermarried.

...（一段時(shí)間）have/haspassedsince+一般過去時(shí)態(tài)句子

Twosistershave/haspassedsincemysistermarried.

Since+時(shí)間點(diǎn)

1.Ihavebeenathomesincethreeo'clockthisafternoon.

2.MariahasbeeninChinasincetwoyearsago.

*everytime,eachtime,nexttime

Everytimeyougetbackatnight,youdropyourbootsonthefloor.

EverytimeIcatchcold,Ihavepaininmyback.

（everytime分寫不可以合寫）比較everyday（adj）日常的，普通的

everyday是名詞短語，每天，天天

NexttimeIgothere,Iwillvisitthem.

*once一旦…就

Onceyoubegin,youmustgoon.你一開了頭，就應(yīng)該繼續(xù)下去。

四、地點(diǎn)狀語從句

地點(diǎn)狀語從句用where,wherever引導(dǎo)

Weshouldgowherethepeopleneedus.我們應(yīng)該去人民需要我們的地方。

Wherethereisawill,thereisaway.有志者，事竟成。

Wherevertheywent,theyreceivedawormwelcome.

無論他們走到哪兒都受到熱烈歡迎。

Shefollowhimwhosehegoes.他無論到哪里她總跟著。

五、原因狀語從句

原因狀語從句用because（因?yàn)椋?，since（既然），as（由于）引導(dǎo)

1、字母由多到少，語氣由強(qiáng)到弱。

2、由why提問必須用because回答。

Since,as不回答why的提問，而且從句一般放在句首，because一般放在主句之后。

3^beforeof+名詞

Becauseoftherain,wedidn，tgotothepark.

4、because和so不可連用，只能選其一。（另有although,but）

Whydidn，thecometoschool?Becausehewasill.

SinceImustdie,Imust.既然我一定要死，我一定這樣做。

Sincealotofpeoplemakemistakesinlife,MrSmithwantedtogiveJohnaChance.

5、for并列連詞，不能放在句首，主要放在兩個(gè)并列句之間。For所提供的理由為一個(gè)補(bǔ)充說明,

而且前面常有逗號(hào)隔開。

Thedaysweshort,foritisDecembernow.

*改錯(cuò)Becauseheisillisthereasonwhyhecan，tcome.（Because改為that）

六、目的狀語從句

目的狀語從句用so（常用于口語），that,sothat,inorderthat引導(dǎo)

目的狀語從句的謂語常含有may,might,can,could,should,would等情態(tài)動(dòng)詞。

1.We，11sitnevertothefrontsowecanhearbetter.

2.Hestudiedhardsothathemightsucceed.他努力學(xué)習(xí)，以便成功。

3.r11speakslowlysothatyoucantakenotes.我慢慢講,以便你們能做筆記。

4.Theyhurriedtothestationinorderthattheycouldcatchthetrain.

他們急忙趕往火車站，以便能趕上火車。

5.ItookataxisothatIcouldgetthereearlier.

6.rmgoingtothelectureearlysothatImaygetagoodseat.

我打算早些去聽講座，以便找個(gè)好座位。

七、條件狀語從句

條件狀語從句由if,unless,(so)aslongas(只需)引導(dǎo)

在條件狀語從句中要用一般時(shí)表示將來時(shí)(與時(shí)間狀語從句相同)

Wewillmissthetrainifyoudon，thurry.

Hesaidwewouldmissthetrainifwedidn，thurry.

Youwillfailtheexamunlessyoustudyhard,(ifyoudon，tstudyhard)

Hewon，tcomeunlessheisinvited,(ifheisn，tinvited)

Eatlessfoodunlessyouwanttobecomefatter,(ifyoudon，twanttobecomebetter)

Aslongasyouarenotafraidofdifficulties,youaresuretosucceed.

Aslongasyoudon，tloseheart,youwillsucceed.

八、結(jié)果狀語從句

結(jié)果狀語從句由such…that,so….that,sothat,that引導(dǎo)

1.such…that的常用句型

such+a/an+形容詞+可數(shù)名詞單數(shù)+that

such+形容詞+可數(shù)名詞單數(shù)+that

Such+形容詞+可數(shù)名詞復(fù)數(shù)(不可數(shù)名詞)+that

注意somany(much,few,little)+名詞，suchalotof(或lotsof)+名詞是慣用法，不可亂

用。

Sheissuchabeautifulgirlthatwealllikeher.

Theyweresuchbeautifulflowerthatweboughthome.

Itwassuchdeliciousfoodthattheyateitup.

2.so+形容詞或副詞+that

so+形容詞+a/an+可數(shù)名詞單數(shù)+that

Heissorichthathecanbuylotofthingsforhimself.

Heworkssohardthathedideverythingwell.

Itwassohotadaythatweallwentswimming.

Itwassuchagooddaythatweallwentswimming.

3.sothat,that都可以引導(dǎo)結(jié)果狀語從句

Hedidn，tstudyhard,(so)thathefailedtheexam.

4.too…to,enough-?*to可以引導(dǎo)結(jié)果狀語從句與so…that替換，so…that結(jié)構(gòu)可以用too…to

替換必須具備兩個(gè)條件，一是主句和結(jié)果狀語從句的主語必須一致，二是從句中的謂語部分必須含

有can(could)not.

Sheisyoungthatshecan，tgotoschool.

Sheistooyoungtogotoschool.

Sheisn，toldenoughtogotoschool.

九、讓步狀語從句

although,though

eventhough=evenif,whether…or

however=nomatterhow

whatever=nomatterwhat

whoever=nomatterwho

whenever=nomatterwhen

wherever=nomatterwhere

"although和though都表示“雖然”只是although更正式，多用于句首,而though用于句中，

二者都可與yet,still連用，但不與but連用

Although/Thoughtheyarepoor,theyoftenhelpothers.

Theyarepoor,buttheyoftenhelpothers.

Althoughhehasfailedmanytimes,hedoesn，tgiveuptrying.

Whatever/Nomatterwhatyousay,Iwon，tbelieveyou.

Nomatterwhatyousay,Idon，tcare.

Nomatterwhoyouare,youmustobeytherulesofourschool.

Howeverhardhetried,hefailedagain.

Nomatterwhattheweatherislike,youcanalwaysfindsurfersoutridingthewaves.

十、方式狀語從句

方式狀語從句由as(如同，按照)，asif(though)引導(dǎo)

*as和like都有“像”的意思，as是連詞，后面連接句子，like是介詞后面可加名詞、代詞或名

詞性短語。

Ididtheworkasothersdid.相當(dāng)于Ididlikeothers.

YoumustdoasIdo.

asif(though)兩者意義相同，從句謂語動(dòng)詞常用虛擬語氣，但實(shí)現(xiàn)可能性較大，則用連接詞。

Itseemsasif/thoughit'sgoingtorain.

Theyaretalkingasif/thoughtheywereoldfriends.

ShetreatsmeasifIwereherbrother.

Whenyouareinhome,doastheRomansdo.

例YoumustdoItoldyou.

A.afterB.beforeC.whereD.as(D)

Thestudentsmustdotheteachertoldthem.

A.asB.beforeC.afterD.if(A)

十一、比較狀語從句

比較狀語從句由as…as,notas(so)…as,than,the+比較級(jí)，the+比較級(jí)引導(dǎo)

Heswimsaswellasyou.(do)

Hedoesn，tswimaswellasyou(do).

Hegothereearlierthanyou.(did)

Thebusierheis,thehappierhefeels.

例題狂學(xué)

鞠嘲嘲

一：?jiǎn)雾?xiàng)選擇

1.Don'tbeafraidofaskingforhelpitisneeded.

A.unlessB.sinceC.althoughD.when

2.Agoodstorytellermustbeabletoholdhislisteners9curiosityhereachestheendofthestory.

A.whenB.unlessC.afterD.until

3.Iknowthemoneyissafe,Ishallnotworryaboutit.

A.EventhoughB.UnlessC.AslongasD.while

4Youwillsucceedintheendyougiveuphalfway.

A.evenifB.asthoughC.aslongasD.unless

5.“Washisfatherverystrictwithhimwhenhewasatschool?^^“Yes.Hehadneverpraisedhimhebecame

oneofthetopstudentsinhisgrade.^^

A.afterB.unlessC.untilD.when

6.Isuggest,healwaysdisagrees.

A.HoweverB.WhateverC.WhicheverD.Whoever

7.Youshouldputonthenoticesallthepeoplemayseethem.

A.whereB.inwhichC.atD.forthem

8.shegoes,therearecrowdsofpeoplewaitingtoseeher.

A.WhereverB.HoweverC.WhicheverD.Whoever

9.Maryclappedherhandoverhermouthsherealizedwhatshehadsaid.

A.whileB.assoonasC.suddenlyD.then

10.________herfaults,she'sArnold'smother.Don'tbesorudetohe匚

A.WhateverB.WhatC.WhicheverD.Whenever

11.____you'regotachance,youmightaswellmakefulluseofit.

A.NowthatB.AfterC.AlthoughD.Assoonas

12.IthoughtshewastheverygirlthatIshouldmarry_______Imether.

A.firsttimeB.forthefirsttimeC.thefirsttimeD.bythefirsttime

13.Don'tplaybytheriver_______youfallinanddrown!

A.incaseB.sothatC.inorderthatD.when

14.Whydoyouwantanewjob____you'vegotsuchagoodonealready?

A.thatB.whereC.whichD.when

15.Heisbetterthan_______Ilastvisitedhim.

A.whenB.thatC.howD.which

1.選Dowhen意為“在（當(dāng)）......時(shí)候:其余三項(xiàng)填入空格處，句意不通。

2.選D。until意為“直到”，句意為“一位優(yōu)秀的故事講述者必須能夠讓聽眾在故事結(jié)束前一直保持好奇心”。

3.選Coaslongas意為“只要”，全句意為“只要我知道這錢是安全的，我就不會(huì)擔(dān)心了，類似地，下面一

題也選aslongas：

“Whatarcyougoingtodothisafternoon??'THprobablygoforawalklateronitstays

A.asfarasB.aslongas

C.evenifD.asif

4.選Dounless意為“如果不”、“除非”，用以引導(dǎo)一個(gè)條件狀語從句。

5.選Co考查not...until...句式，其意為“直到……才……

6.選B。whatever引導(dǎo)的是讓步狀語從句，相當(dāng)于nomatterwhat。注意不能選A,因?yàn)閟uggest是及物動(dòng)

詞，它應(yīng)帶自己的賓語，而however不能用作賓語。

7.選A。where指“在……的地方”，用以引導(dǎo)地點(diǎn)狀語從句。

8.選A,wherever意為“無論什么地方

9.選Bo根據(jù)語境可推知。如下面一題也選assoonas：

hebecamerichhecastasideallhisoldfriendswhogavehimsomehelp.

A.WhileB.Assoonas

C.SuddenlyD.Then

10.選A。whateverherfaults為讓步狀語從句，句末省略了謂語動(dòng)詞are?

11.選Aonowthat為連詞，用以引導(dǎo)原因狀語從句，其意為“既然"，與since同義。其中的mightaswell

意為“不妨”。全句意為“既然你得到一個(gè)機(jī)會(huì)，你不妨充分利用它工

12.選C。thefirsttime在此用作連詞，用以引導(dǎo)狀語從句。句意為“我第一次見到她就認(rèn)為她很誠(chéng)實(shí)”。

13.選C。incase意為"以防

14.選Dowhen不表示“當(dāng)……的時(shí)候”，而表示“既然”，相當(dāng)于since,用以引導(dǎo)原因狀語從句。全句意為:

你既然已經(jīng)有了這么好的工作，干嗎還要找新的工作呢？請(qǐng)?jiān)賰衫?/p>

Ican'ttellyouwhenyouwon'tlisten.既然你不想聽，我就不告訴你了。

Whyusewoodwhenyoucanuseplastic?既然能用塑料，為什么還要用木料？

15.選A。than后省略了hewas,假若補(bǔ)充完整，全句即為HeisbetterthanhewaswhenIlastvisitedhim.

練習(xí)狂練

二.完形填空

Thirty-six-year-oldBobBlackisaworkaholic.Heisalwayssittingathisdeskand_21—throughhis

paperwork.Bob___22___wakesupaboutfiveminutesbeforehisalarmclock___23___.Assoonashe

hearsmyalarmclock,hewilljumpoutofhisbed.It_24___himlessthanfifteenminutestowash,get

___25_,havebreakfast,leavehomeandgetonabus.Bobisalwaysthefirstperson_26___theoffice.

Themorningsarealwaysverybusyandtheafternoonsareeven__27—!Meetingsandphonecalls

—28___alargepartoftheday.Everyminuteofthedayis_29___urgentmatters.By_30___eight

o'clock,Bobusuallyfindssometimetodohisownpaperworkand_31___someofhispersonale-mails.

WhenBobgetshomeataboutten,hewilllookatsomedocumentsthathebringsbackfromtheofTice

—32—hecanbereadyforthenext_33___work.Bobgetstobedaroundmidnight_34—hiswifeand

childrenarealready_35__.Bob_36_hastimeforfunandotheractivitieswithhisfamily.Hisfamily

—37___aboutit.Buthetriestoworkhardsothathecan_38—moremoneyforhisfamily._39___,

Bobwillget_40___ifthere5snothingtodo.Helikesbeingbusy.

21.A.workingB.workC.worksD.worked

22.A.unfortunatelyB.friendlyC.normallyD.finally

23.A.switchonB.goesoffC.switchoffD.turnover

24.A.tookB.spendC.spentD.takes

25.A.changeB.changingC.tochangeD.changed

26.A.togettoB.gettoC.getstoD.gettingto

27.A.busyB.relaxingC.busierD.relaxed

28.A.takeoverB.takeupC.takeoffD.takeout

29.A.filledwithB.filledofC.fullwithD.fulledof

30.A.atB.aroundC.fromD.in

31.A.tellB.makeC.callD.answer

32.A.inorderB.inordertoC.sothatD.soasto

33.A.dayB.daysC.days'sD.day's

34.A.whenB.whileC.becauseD.since

35.A.sleepB.asleepC.wakeD.awake

36.A.seldomB.everC.oftenD.few

37.A.complainsB.comesC.talksD.thinks

38.A.payB.makeC.takeD.cost

39.A.BesideB.HoweverC.LuckilyD.Besides

40.A.excitingB.boringC.boredD.excited

三.閱讀理解

Ifwewereaskedexactlywhatweweredoingayearago,weshouldprobablyhavetosaythatwe

couldnotrememberButifwehadkeptabookandhadwritteninitanaccountofwhatwedideachday,

weshouldbeabletogiveananswertothequestion.

ItisthesameinhistoryManythingshavebeenforgottenbecausewedonothaveanywritten

accountofthemSometimesmendidkeeparecordofthemostimportanthappeningsintheircountry,but

oftenitwasdestroyedbyfireorinawar.Sometimestherewasneveranywrittenrecordatallbecausethe

peopleofthattimeandplacedidnotknowhowtoWrite.Forexample,weknowagooddealaboutthe

peoplewholivedinChina4,000yearsago,becausetheycouldwriteandleavewrittenrecordsforthose

wholivedafterthem.Butweknowalmostnothingaboutthepeoplewholivedeven200yearsagoin

centralAfrica,becausetheyhadnotlearnedtowrite.

Sometimes,ofcourse,evenifthepeoplecannotwrite,theymayknowsomethingofthepast.They

haveheardaboutitfromolderpeople,andoftensongsanddancesandstorieshavebeenmadeaboutthe

mostimportanthappenings,andthesehavebeensungandactedandtoldformanygenerationsFormost

peopleareproudtotellwhattheirfathersdidinthepast.ThiswemaycallRememberedhistory9.Some

ofithasnowbeenwrittendown.Itisnotsoexactorsovaluabletousaswrittenhistoryis,becausewords

aremuchmoreeasilychangedwhenusedagainandagaininspeechthanwhencopiedinwriting.But

wheretherearenowrittenrecords,suchspokenstoriesareoftenveryhelpful.

Passage3

當(dāng)我們被問起準(zhǔn)確的說書一年之前的這個(gè)時(shí)候我們正在做什么，我們可能不得不承認(rèn)記不得了。但

是，如果我們有個(gè)冊(cè)子，上面記錄了每天我們做過什么的話，這個(gè)問題就不難給出答案了。

對(duì)于歷史的記錄也是如此。許多事情由于沒有任何書面的記錄而被人遺忘。有時(shí)也有人會(huì)對(duì)于他們

國(guó)家發(fā)生的重要事件進(jìn)行記錄，但是這些記錄往往毀于火災(zāi)或者戰(zhàn)亂。有時(shí)也因?yàn)槟莻€(gè)地方或那個(gè)

時(shí)代的人不會(huì)寫字，而根本不會(huì)有書面記錄的存在。譬如說，因?yàn)橹袊?guó)4千年前的古人會(huì)寫字而且

給后人留下了很多文獻(xiàn),所以我們對(duì)那個(gè)時(shí)代的中國(guó)人十分了解;但是對(duì)于甚至2百年前的中非人，

由于他們不會(huì)寫字，而使我們對(duì)其幾乎一無所知。

當(dāng)然了，有的時(shí)候就算人們不會(huì)寫字，對(duì)于過去的歷史也會(huì)多少有些了解。也許是從老一輩的那里

聽說的，或者從一些由重大事件編出的歌曲和舞蹈中了解的——這些傳說和歌舞是從很多輩人流傳

下來的。很多人都喜歡夸耀他們的父輩在過去的豐功偉績(jī)，我們把這個(gè)叫做“rememberedhistory"

(記憶中的歷史)。現(xiàn)在一些記憶中的歷史己經(jīng)變成了文字而保留了下來。由于反復(fù)經(jīng)過口頭傳送

的歷史遠(yuǎn)比書面記錄的歷史變化大，這種歷史不如書面歷史那么精確和有價(jià)值。但是，在沒有書面

歷史存在的時(shí)候，這種口頭流傳的故事就很有幫助了。

41.Whichofthefollowingideasisnotsuggestedinthepassage?(D)

A.”Rememberedhistory”,comparedwithwrittenhistory,islessreliable

B.Writtenrecordsofthepastplaythemostimportantroleinourlearningofthehumanhistory.

C.AwrittenaccountofourdailyactivitieshelpsUStobeabletoanswermanyquestions.

D.Wheretherearenowrittenrecords,thereisnohistory.

42.WeknowverylittleaboutthecentralAfrica200yearsagobecauseD

A.therewasnothingworthbeingwrittendownatthattime

B.thepeoplethereignoredtheimportanceofkeepingarecord

C.thewrittenrecordswereperhapsdestroyedbyafire

D.thepeopletheredidnotknowhowtowrite

43."Rememberedhistory^refersto_D_.

A.historybasedonaperson'simagination

B.storiesofimportanthappeningspasseddownfrommouthtomouth

C.songsanddancesaboutthemostimportantevents

D.bothBandC

44."Rememberedhistory^isregardedasvaluableonlywhenB.

A.itiswrittendownB.nowrittenaccountisavailable

C.itprovestobetimeD.peopleareinterestedinit

45.Thepassagesuggeststhatwecouldhavelearnedmuchmoreaboutourpastthanwe

donowiftheancientpeoplehadA

A.keptawrittenrecordofeverypasteventB.notburnttheirwrittenrecordsinwars

C.toldexactstoriesofthemostimportanthappeningsD.mademoresongsanddances

Treesareusefultomaninthreeveryimportantways：theyprovidehimwoodandotherproducts；they

givehimshade；andtheyhelptopreventdrought（干旱）andfloods.

Unfortunately,inmanypartsoftheworld,manhasnotrealizedthatthethirdoftheseservicesisthe

mostimportant.Inhiseagernesstodrawquickprofitfromthetrees,hehascutthemdowninlarge

numbers

Twothousandyearsago,arichandpowerfulcountrycutdownitstreestobuildwarships,withwhich

togainitselfanempireItgainedtheempirebut,withoutitstrees,itssoilbecamebareandpoor.Whenthe

empirefelltopieces,thecountryfounditselffacedbyfloodsandstarvation.

Evenwhereagovernmentrealizestheimportanceofaplentifulsupplyoftrees,itisdifficult

sometimestomakethepeoplerealizethis.Theycutdownthetreesbutaretoocarelesstoplantandlook

afternewtreesSo,unlessthegovernmenthasagoodsystemofcontrol,orcaneducatethepeople,the

forestsslowlydisappear

Thisdoesnotonlymeanthattherewillbefewertrees.Theresultsareevenmoreserious：forwhere

therearetrees,theirrootsbreakthesoilup,allowingtheraintosinkin,andalsobindthesoil.This

preventsthesoilfrombeingwashedaway.Butwheretherearenotrees,therainfallsonhardgi*oundand

flowsawayonthesurfece,andthiscausesfloodsandtheraincarriesawaytherichtopsoilinwhichcrops

growWhenallthetopsoilisgone,nothingremainsbutworthlessdesert.

Passage3

樹木對(duì)于人來說有3個(gè)重要益處：樹木給人類提供木材和其他產(chǎn)物；樹木可以讓人們乘涼；樹木可

有效地防止旱澇災(zāi)害。

可惜的是，在世界上許多地方，人類沒有認(rèn)識(shí)到以上三個(gè)作用中，第三個(gè)是最重要的。人們急切于

從樹木上快速的謀取利益，于是大量的砍伐森林。

兩千年之前，有一個(gè)富裕和強(qiáng)大的國(guó)家。為了建立帝國(guó)，砍倒了樹木來造戰(zhàn)艦。帝國(guó)建立了，但是,

沒有樹木的土地變得荒蕪和貧瘠。當(dāng)?shù)蹏?guó)四分五裂的時(shí)候,整個(gè)國(guó)家發(fā)覺自己面臨的是水災(zāi)和饑荒。

就算在政府認(rèn)識(shí)到足夠的樹木儲(chǔ)備的重要性時(shí)，有時(shí)卻很難讓人民也意識(shí)到這點(diǎn)。人們砍倒了樹木，

卻疏于種植和照料樹苗。因此，除非政府建立一套體制來控制或者教育人們，否則森林就會(huì)漸漸消

失。

森林的消失不僅僅意味著樹木的減少，還有更嚴(yán)重的后果。在有樹的地方，樹根不僅把土壤粉碎成

小塊，便于雨水的滲入，還可以牢牢的抓住泥土，防止泥土被沖刷走。但是在沒有書的地方，雨水

直接落在堅(jiān)硬的地面，在土地表面流走。這不僅會(huì)導(dǎo)致洪水，雨水還會(huì)帶走莊稼賴于生長(zhǎng)的肥沃的

表層土。當(dāng)所有的表層土被沖走之后，除了毫無價(jià)值的沙漠之外，什么也沒有了。

41.Treesareusefultomanmainlyinthreeways,themostimportantofwhichisthattheycanD

A.keephimfromthehotsunshineB.enablehimtobuildwarships

C.makehimdrawquickprofitfromthemD.protecthimfromdroughtsandfloods

42.IfsagreatpitythatC

A.manisonlyinterestedinbuildingempiresB.maniseagertoprofitfromtrees

C.manhasn'trealizedtheimportanceoftreestohimD.manhasn'tfoundoutthathehaslostalltrees

43.SoonerorlatertheforestswilldisappearC

A.unlessacountryhasaplentysupplyoftreesB.unlesspeoplestopcuttingdowntheirtrees

C-unlessallpeoplearetaughttheimportanceofplantingtrees

D.unlessthegovernmentpunishesthosewhocuttreesinsteadofplantingthem

44.Theword"bind”inParagraph5means"C"

A.towashawayB.tomakewetC.tomakestayt