英語自學-第二外語

LessonOne

Text

apen

Itisapen.

adesk

Itisadesk.

amap

Itisamap.

akey

Itisakey.

ClassroomEnglish

Goodmorning,comrades.

Goodmorning.

LessonTwo

Text

Thisisabook.

Itisagoodbook.

Thatisatable.

Itisanewtable.

—Isthisameter?

—Yes,itis.It'sameter.

—Isthatameter,too?

—No,itisn't.It'sabox.

—Isthisamachine?

—Yes,itis.It'sanoldmachine.

—Isthatameter?

—No,itisn't.It'sana.c.motor.

ClassroomEnglish

Standup!

Sitdown,please.

LessonThree

Text

—Isthisamap?

—Yes,itis.

—It'samapofChina.

—Isthatamap?

—No,itisn't.

--It'sapicture.

—Aretheseboxes?

—No,theyaren't.

—Whatarethey?

—They'remeters.

—Arethosebuses?

—No,theyaren't.

—Whatarethey?

--They'retrucks.

—Whatarethese?

—They'resteelpipes.

—Whatarethose?

--They'reglasstubes.

ClassroomEnglish

Heregoesthebell.

Openyourbooksatpage...

LessonFour

Text

Iamaworker.

Weareworkers.

Youareateacher.

Youareteachers.

Heisastudent.

Theyarestudents.

Sheisadoctor.

Theyaredoctors.

Wearegoodfriends.

Wecomefromdifferentpartsofthecountry.

Weworkhardforourcountry.

—Areyouaworker?

—Yes,Iam.

—Isheateacher?

—No,heisn't.

-Whatishe?

—He'sastudent.

—Areyouworkers?

—Yes,weare.

—Aretheyteachers?

—No,theyaren't.

—Whatarethey?

—They'restudents.

ClassroomEnglish

Readthenewwords,please.

Readafterme,please.

LessonFive

Text

IhaveanEnglishbook.

Itishereonthedesk.

IreadEnglisheverymorning.

Youhavearadio.

Itisthereonthetable.

YoulistentoRadioBeijingeveryday.

HehasaTVset.

Itisnearthewindow.

HeandhisfriendswatchTVintheevening.

—HaveyouanyEnglishbooks?

—Yes,Ihavesome.

—Hashearadio?

—Yes,hehas.

—HassheaTVset?

—No,shehasn't.

ClassroomEnglish

Let'sreadthetext.

Lookattheblackboard,please.

LessonSix

Text

OurClassroom

Thisisourclassroom.Itisverylarge;itisbrightandclean.

Thereisadoorontheright.Therearefourwindowsontheleft.

Theyareopen.

Thisistheteacher'sdesk.Thereisataperecorderonit.

Thosearethestudents5desks.TheyaremanyEnglishtextbooks

onthem.

Onthefrontwallthereisablackboard.Onthebackwallyou

canseetwomaps.OneisamapofChina;theotherisamapofthe

world.

Classesbeginateight.WehaveEnglishlessonshere.We

listentotheteacherattentively.Therearethirtystudentsinour

class.Weallworkveryhard.

ClassroomEnglish

Listentome,please.

What'stheEnglishfor...?

Let'shaveabreak.

LessonSeven

Text

Mylifeattheuniversity

IamaphysicsstudentatBeijingUniversity.Mylifehereis

veryinteresting.Therearesomanynewthingstolearn.Westudy

physics,mathematicsandEnglish.Ilikethemverymuch.

EverydayIgetupearlyandgoouttodomorningexercises.

Wehaveclassesmostofthemorning.Intheafternoonwe

reviewlessons.Sometimes,wedoexperimentsinphysics.

IntheeveningwelistentoanEnglishbroadcastordoour

homework.Wegotobedataboutten.

--What'syourname?

—Myname'sLiHua.

—Whichclassareyouin?

—Fminclassone.

--Where'reyoufrom?

一I'mfromBeijing.

—Doyougetupearlyeveryday?

—Yes,Ido.

—Howmanyperiodsdoyouhaveinthemorning?

—Wehavefourperiodsinthemorning.

—Doyouhaveanylessonsintheafternoon?

—No,wedon't.

—CanyouspeakandwriteEnglish?

—Yes,Ican,butonlyalittle.

—DoyoulikeEnglish?

—Yes,Ilikeitverymuch.

--I'mgladtohearthis.

ClassroomEnglish

Timeisup.

That'sallfortoday.

Good-bye,comrades.

LessonEight

Text

Whatdoesthemandowithhisbrain?

Manhasabigbrain.Hecanthink,learnandspeak.Some

scientiststhinkthatmenaredifferentfromanimalsbecausethey

canthinkandlearn.Othersthinkthatmenaredifferentfrom

animalsbecausetheycanspeak.Animalscannotspeak.They

makenoisewhentheyareafraid,angryandunhappy.Apescan

understandsomethingsquickly,buttheyaredifferentfrommen.

Theycannotjoinwordsandmakesentences.Theycannotthink

likemenbecausetheyhavenolanguage.Theycanneverthink

aboutthepastorthefuture.Languageisawonderfulthing.Man

canspeakhisownlanguageverywellwhenheisfourorfive,but

noanimallearnstospeak.Howdochildrenlearn?Scientistsdo

notreallyknow.Whathappenswhenmenspeak?Scientistsdonot

know.Theyonlyknowthatmancanspeakbecausehehasabig

brain.

ClassroomEnglish

Let'sreadthetext.

Readaloud,please.

Nowlet'sdotheexercises.

ReadingMaterial

TheBrownsandtheGreens

TherearefivepeopleintheBrownfamily.TheBrownsare

fromLondon.Mr.Brownisascientist.Hestudiesthedifference

betweenmenandanimals.Mrs.BrownisanEnglishteacher.

Theyhavethreechildren,asonandtwodaughters.Onedaughter

teachesinatechnicalschool.HernameisMary.Theother

daughter,Jane,isastudentinhighschool.Theirson'snameis

John.JaneandJohngotothesameschool.Theystudyveryhard.

Theylikemathematicsandphysicsverymuch.Janewantstobea

scientist.Johnwantstobeanengineer.

TherearefourpeopleintheGreenfamily.TheGreensare

fromCalifonia.Mr.andMrs.Greenarefarmers.Theirson,Peter,

worksinafactoryduringthedayandstudiesphysicsata

universityintheevening.Hewantstobeaphysicist.Their

daughter,Ann,isastudentinhighschool.

LessonNine

Text

TheExperiment

Theexperimentisabasicscientificmethod.Scientistusually

basetheoriesontheirobservationsandthentesttheirtheoriesby

experiments.Theyusespecialapparatustomakeobservationsand

carryouttheirexperiment.

Herearetwoverysimpleexperiments.Nowlookatthe

PictureA.

Whatexperimentisthemandoing?

Heismakinguseoflightfromthesuntolightamatch.

Whatinstrumentisheusing?

Heisusingamagnifyingglass.

Whatdoesthisshow?

Itshowsthatlightisaformofenergy.

LookatthePictureB.Takethreecandlesofthesamesize

andtwoglasses,oneisbig,theotherissmall.Standthethree

candlesapartandlightthem.Nowtheyareallburning.Coverthe

firstonewiththesmallglassandthesecondonewiththebigglass.

Thelastoneisburningintheopen.Whichcandleflamediesout

first?Whichcandlecontinuestoburn?Whatdoesthisshow?

ClassroomEnglish

TranslatethesentenceintoEnglish.

Handinyourexercise-books,please.

ReadingMaterial

Inthephysicslaboratory.

Therearemanylaboratoriesinouruniversity.Ourphysics

laboratoryisnearthelibrary.Weoftengotheretodoour

experiments.Ourteachergoestherewithus.

Allthestudentsinthelaboratoryareverybusytoday.Weare

doingourlabwork.LookatJohnandPeter.Theyaremeasuring

thecurrent.Maryisbusy,too.Sheistakingthereadings.Theyare

workingcarefully.Ourphysicsteacherworkshereevery

afternoonandhelpsuswithourlabwork.Nowsheisstanding

besidetheblackboard.

Thelaboratorytechnicianbythewindowisshowingsome

studentshowtoreadthemeters.Thosestudentsarestudying

high-energyphysics.Theyareallhopingtobescientists,and

physicsisanimportantcourseforsciencestudents.

Throughexperimentswecanunderstandphysicsbetter.We

alsocarryoutresearchworkhere.

LessonTen

Text

Edisontheinventor

ThomasAlvaEdisonwasagreatinventorandverypractical

man.

Asalittleboy,helikedtoaskquestions.Hewantedtoknow

anything.

Whenhewastwelve,Edisonbegantomakehisownwayin

theworld.Hesoldnewspapersonthetrains.Thiswashisfirstjob.

WhenhefirstwenttoDetroithevisitedthePublicLibraryand

sawmanybooks.Hemadeuphismindtoreadallthebooksthere.

Atfifteenheestablisheda“l(fā)aboratory“onhistrain.Itwas

theworld'sfirstlaboratoryonwheels.Hemadeexperimentsthere.

SixyearslaterhewenttoNewYork.Thereheworkedfor

sometimeasatelephoneoperator.Butsoonhetookaninterestin

inventions.Inaveryshorttimeinventionsbecamehislife'swork.

Hewantedtoinventnewwaystouseelectricityfortheinterestsof

people.Buthehadnomoney.In1868,heinventedaninstrument

andthensoldit.WiththismoneyEdisoncouldestablishhisown

laboratoryandgetsomeotherscientiststohelphim.

ForsixtyyearsEdisonwastheworld'sleadinginventor.He

mademany,manyinventions.Hisinventionschangedourwayof

living.

ClassroomEnglish

May1askaquestion?

Answermyquestion,please.

ReadingMaterial

Mary'sbirthdaypresents

Whenshewasachild,MaryGreentookagreatinterestin

Livingthings.Now,sheisagoodsciencestudent.Shestudies

biologyatouruniversity,andlikesverymuch.

Shewantstosetupalaboratoryathome.

Yesterdaywasherbirthday.Onherbirthday,shewantedher

familytogiveherusefulpresents,soalltheirpresentshad

somethingtodowithbiology.Herfatherboughtherasetof

dissectinginstruments.Itwasveryexpensive,buthedidnotmind

becausehewantedMarytodowellinherstudies.Hermother

gaveheramicroscope.Itwasexpensive,too,butitdidnotcostas

muchasthedissectingset.Mary'ssistergaveherasetofslides,

andherlittlebrotherboughtherabook—abookofexperiments.

Hesaidhelikedbooksmost,andMaryagreedwithhim.Withall

theseusefulpresents,shecansetupherownlaboratorynow.

LessonEleven

Text

Counting

Howdidtheearlypeopledotheircounting?Itisvery

interesting.Intheearlydayspeoplecouldnotcountaswedo.

Theirmethodwasverysimple.Atfirsttheydidalltheircounting

withsmallstones.Later,theylearnedtousetheirfingersin

counting.Sincemanhastenfingers,thenumbertenbecamethe

foundationofallcountinginmanypartsoftheworld.This

decimalsystemledgraduallytoabranchofmathematics.Wecall

itarithmetic.

Nowwecanmakeaccuratecomputationswithelectronic

computers.Computercanworkveryquicklyandaccurately.For

example,amodemelectroniccomputercandoovertenmillion

computationsinonesecond.

Thefirstelectroniccomputerswentintooperationin1946.

Sincethengreatchangeshavetakenplaceinscienceand

technology.Withthehelpofcomputersproductivityhasincreased

greatly.Computersareofgreathelptous.Thatiswhyinrecent

yearselectroniccomputerhavefoundwideapplicationnotonlyin

productionandscientificresearch,butalsoeverydaylife.

ClassroomEnglish

Isthatcleartoyounow?

Arethereanyquestions?

ReadingMaterial

Somethingaboutthecomputer

In1946thefirstelectroniccomputerswentintooperation,

sinceitsinventionthecomputerhasundergonemanychanges,and

ithasfoundmoreandmoreapplication.Itcanfreepeoplefrom

complicatedmeasurementandcomputation.

Accuratemeasurementandexactcomputationarethebases

ofmodernengineeringandscientificresearch.Forexample,

scientistsusuallytesttheirtheoriesbypracticalexperiments.They

havetomakemanycomputationsbeforetheycansaythatthe

resultsoftheirexperimentsarecorrect.Yettherearecomplex

computationsinscienceandengineering.Scientistsareunableto

makethem.Butthecomputercandothemquicklyandaccurately.

Inrecentyearsmoreandmorepeoplehaveusedcomputersnot

onlyinproductionandtechnology,butalsoineverydaylife.

LessonTwelve

Text

AtriptotheMoon

Themoonisafamiliarobjecttoyou.Youarefamiliarwith

itsbeautifulface.Butdoyouwanttoknowmoreaboutit?

Well,let'stakeatriptothemoon.Itwillbeaverylongtrip,

forthemoonis240000milesaway.Ifwegobytrainataspeedof

sixtymilesanhour,thetripwilltakeoverayear-sixmonthseach

way.Infact,notraincangothere.

Canwegotherebyaeroplane?Wecan't,forthereishardly

anyaironcewehavegottenmilesawayfromtheearth.An

aeroplanecannotflywithoutair.

Nowwecanmakethetripbyspaceship.Rocketscanshoot

ustothemoon.Supposethatwereallygetthere,weshallbeina

quitedifferentworld.

Therearenocloudsonthenoon,forthereisnowater.There

arenoplants,andtherearenoanimals.Thereisnothingliving;or,

iftherearelivingthings,theyarenotatalllikethelivingthingsof

thisearth.Thereisnoaironthemoon.Withoutairtherecanbeno

sound.Besides,youwillfeelverylightonthemoon.Dayonthe

moonlastsfortwoweeks.Duringthedaythesunisveryhot.On

theothersideofthemoonisnight.Thenightisverycold.

Doyouwanttostayonthemoon?Ifnot,letusgetintoour

spaceshipquicklyandgohome.

ClassroomEnglish

Takeoutyourexercise-books.

We'llhaveashortdictation.

ReadingMaterial

Air

Alayerofairsurroundsourearthcompletely.Wecallitthe

atmosphere.Withouttheatmosphere,weshallnotbeabletolive

ontheearth.Therewillbenoairforustobreathe.Theearthwill

bevery,veryhotinthedayandvery,verycoldduringthenight.

Airisallaroundus.Itisaroundusaswewalk.Whenwesit

down,itisaroundus.Whenwegotobed,airisalsoaroundus.

Weliveinair.

Alllivingthingsneedair.Livingthingscannotlivewithout

air.Wecangowithoutfoodorwaterforafewdays,butwecannot

liveforafewminuteswithoutair.Webreatheinair.

Weneedairinordertolive.Doyouknowthatfirestooneed

airinordertoburn?Ifthereisnoairyouwillnotbeabletomake

afire.

Weknowthatairisarounduseverywhere.Wecannotseeair

butwecanfeelit.Simpleexperimentswillshowthatairoccupies

spaceandhasweight.

LessonThirteen

Text

Forecastingweather

Amanhadtwodaughters.Oneofthemwasmarriedtoa

farmer,theothertoapotter.Onedaytheskywascoveredwith

clouds.Hesetouttovisitthem.Andwhatdidhesee?Thefarmer

wasprayingfortherain,whilethepotterwasprayingforafine

day.

Thislittlestoryshowshowmuchmanhasfeltconcerned

abouttheweather.Indeed,theweatherhasaffectedhislifegreatly.

Therefore,menhavealwaystriedtoobserve,forecastandcontrol

theweather.Nowweather-forecastinghasbecomeanewscience.

Weatherisdifferentfromclimate.Itisthecurrentstateofthe

atmosphere,whileclimateistheaveragestateoftheatmosphere

overalongperiodoftime.Weatherchangesconstantly,while

climateiscomparativelystable.

Weather-forecastingisorganizedallovertheworld.There

aresome700stationsdifferentpartsoftheworld.Recently,

satelliteshavebeenusedforthestudyofweather.

Nexttoobservationandprediction,theaimofscienceisto

changeandcontroltheweather.Muchofthisefforthasbeen

directedtosmall-scaleweathercontrol.

Ifwecancontroltheweathersuccessfullysomeday,who

knowswhatmayhappenbetweendifferentcountiesoftheworld!

Weathercontroloveronecountrymightadverselyaffectthe

weatherofanothercountry.

ClassroomEnglish

Doyouunderstand?

Yes,Ido.

Sorry,Idon't.

Pleasesayitagain.

ReadingMaterial

Water

Waterisveryimportanttolivingthings.Withoutwaterthere

canbenolifeontheearth.Allanimalsandplantsneedwater.Man

alsoneedswater.Weneedwatertodrink,tocookourfoodandto

cleanourselves.Waterisneededeverywhere.

Asrainbeginstofallfromclouds,itisverypure.However,

asitfallsthroughtheairitdissolvessomeofthegasesintheair.It

alsocollectsdustandmicrobesintheair.

Whentheraingetsthegrounditcollectsmoredustand

microbes.Someoftheimpuritiesareharmful,whileothersarenot.

Manymicrobesareharmful.Theyaresosmallthatwecannotsee

them.Thesemicrobesmustberemovedorkilledbeforethewater

issuitablefordrinking.

Watermaybeasolid,aliquid,oragas.Whenitisasolid,it

iscalledice.Itmaybeveryhard.Whenitisaliquid,itcanbe

pouredoutofacontainer.Whenitisagas,itcannotbeseen.

LessonFourteen

Text

Atomsandenergy

Anatomisoftendefinedas“thesmallestparticleofan

element”.Ithasthepropertiesofmatter.Ithasmassandtakesup

space.Anatomcontainsparticlesofmatter.Theyarecalled

electrons,protons,andneutrons.Itcontainsotherparticles,too.

SomeparticlesinanatomhavepropertiesElectronshave

negativechargesandprotonshavepositivecharges.Particleswith

unlikechargesareattractedtoeachother.Buttheelectronsofan

atomdonotmovetotheprotonsinthenucleus.Theyarekept

apartbyforces.Theparticlesinanatommoveatgreatspeeds,but

theyusuallystaywithintheatom.

Anatomisabitofmatter.Anatomcanalsobethoughtofas

smallpackageofenergy.Justasapackagecanbeopenedtoget

whatisinside,energycanbeobtainedfromanatom.Theenergy

fromatomshasalwaysbeenusedbyman.The“package”of

nuclearenergyhasbeen“opened”.

Energyisnoteasilydefined.Itisusuallydefinedas”the

abilitytodowork”.Workisdonewhenforceisusedtomovean

abjectthroughadistance.Amovingcarhasenergy.Itcanmove

peopleorthingsfromplacetoplace.

Thereareseveraldifferenttypesofenergy.Forexample,the

energyofthingsinmotioniskineticenergy.Whenacaris

moving,ithaskineticenergy.Anothertypeofenergyispotential

energy.Mattercontainspotentialenergybecauseofitspositionor

shape.Whenastoneislifted,ithaspotentialenergy.

ClassroomEnglish

PutitintoChinese,please.

Howdoyouspelltheword...?

ReadingMaterial

Electricity

Electricitywasdiscoveredagoodmanyyearsago.Itisa

popularformofenergy.Whydoeselectricityfindwideapplication

inourlife?Itisbecauseelectricitycanbeeasilyproducedand

transmittedoveralongdistance.Itcanalsobecontrolledeasily.

Electricenergycanbereadilychangedtoandfrommanyother

formsofenergy,suchasheat,light,ormechanicalenergy.And

thismaybedoneindifferentways.

Electricityisusuallysuppliedbypowerplants.Mostpower

plantsusecoalandoiltoheatwater.Thehotsteamistransmitted

toasteamturbine.Theheatenergyinsteamischangedbythe

turbineintomechanicalenergy;thesteamturbinedrivesan

electricgenerator.Theelectricgeneratorchangesmechanical

energyintoelectricenergy.

Todayelectricityiswidelyusedformanypurposes;yetmany

morearepossible.Withthedevelopmentofscienceand

technology,moreandmoreapplicationsofelectricitywillbe

foundinthefuture.

LessonFifteen

Text

Thesoundbarrierisbroken

Today,manyplanescanflyseveraltimesfasterthansound.

Butforseveralyearsafter1945itseemedthattherewasa“sound

barrier^^,andnoplanecouldbreakthrough.Pilotsfirstmetthis

barrierinthefastestplanesoftheSecondWorldWar.Whenthey

camenearthespeedofthesoundinadive,theirplaneswould

suddenlybegintoshake.Severaltimespilotslosttheirliveswhen,

suddenly,thewingsoftheplaneweretornoff.

Aeroplanedesignersknewthecaseofthis.Theyknewthat

whenaplanecomesnearthespeedofsound,wavesoftheair

buildupinfrontofthewings.Thewingscannotbreakthrough

them.Thebarrierorwallconsistsofthesewavesofair.Aspecial,

rocket-poweredplanewasdesignedtolookintotheproblem.It

wasverystronglybuiltandhadspecialwings.Butstillthepilot

mightbekilledeasily.

In1947atestpilottooktheplaneuponnumberofflights.

Eachtimehecamenearertothespeedofsound.Thenearerhegot,

themoretheplaneshook.Atlasthedecidehewouldbreak

throughthebarrier.Tosavefuel,thespecialplanewastakenup

highabovethecloudsunderabomber.Thenitwasdropped.The

pilotturnedtheengineonandtheplanebegantogetnearertothe

speedofsound.Atonepointitseemedthattheplanewouldbe

tornapartintheshaking.Butsuddenlythepeopleontheground

heardabigsound.Theplanewasflyingfasterthansoundbutvery

smoothly.Thetestshowedthatthesoundbarrierwasnota

problemiftheplanewasdesignedproperly.

ClassroomEnglish

Haveyoualldoneyourhomework?

Trytodoitbetternexttime.

ReadingMaterial

Thepriceofspeed

Amodernairlinerfliesmuchfasterthensound.Apassenger

canleaveLondonatnoonandgettoNewYorkattenthatsame

morning!Thereisafive-hourtimedifferencebetweenthetwo

citiesandtheairlinercanflytheAtlanticinonlythreehours.That

eveningthepassengerwillfeelitistimetogotobed,whenitis

onlysixinNewYork.Theeveningwillonlyjustbegin.Thisis

called'jetlag”.Pilotssufferfromitverymuch.Itmaybeinthe

middleofthenightinHongKongbuttheirstomachsarestillon

Londontime,whereitisdinnertime.Theymustadjusttoconstant

changesintime.Thiscausesmanykindsofproblems.Thatiswhy

pilotsoftenlookmucholderthantheyare.

Airtravelisgettingfasterallthetime.Engineerssaythat

soonpeoplewillbe"shot"totheirdestinationsinbigrockets.

Theserocketswillbeabletocarry170passengersatatime.

But,ofcourse,passengerswillstilltakehourstogettothe

airport.Today,theshortestpartofthetripisintheair.Thelongest

partisontheroadsfromthecenterofcitytotheairport.Theroads

becomemoreandmorecrowedwhileourplanesbecomefaster

andfaster.

LessonSixteen

Text

Canacomputerbecalledan^electronicbrain”？

Multiply38462814by12972032andthendividetheproduct

by356.Howlongdoyouthinkitwilltakeyou?Tryitandsee.It

willtakealongtimetodothis.Thereareevenmorecomplex

computationsinscienceandengineering.Theyaretoolongand

toocomplicatedtobeworkedoutbyafewpeople.

Electroniccomputersworksofastthattheycandothis

exampleinlessthanonesecond.Itisnowpossibletoaddor

subtracttwolargenumbersinoneortwomicroseconds,andto

multiplyordividethemintenortwentymicroseconds.Soa

computercanperformasmucharithmeticinaquarterofanhour

asanefficienttechnicianmightreasonablehopetoachievewith

pencilandpaperinalifetime.

Computersareabletodoextremelycomplicatedworkinall

branchesoflearning.Theycansolvethemostcomplex

mathematicalproblemsorputthousandsofunrelatedfactsin

order.

Mostpeoplecallacomputeran''electronicbrain”.Thisisnot

quiteaccurate.Computersweregiventhattitlebysomemisguided

journalistnotlongafterthefirstmodernelectroniccomputerwas

builtin1946.Therearesimilaritieswiththehumanbrain,but

thereisoneveryimportantdifferent,thatis,thecomputeris

controlledbyman.Althoughitsolvesmany,manyproblemsbetter,

fasterandmoreaccuratelythanmancan,theso-calledelectronic

brainmustbeprogrammedbyahumanbrain.Acomputercando

nothingunlessitistoldwhattodo,whentodoit,andhowtodo

it.

ClassroomEnglish

Wearegoingtotakeupanewlessontoday.

Firstmexplainthenewwords.

Thenwe'llreadthetext.

ReadingMaterial

Electroniccomputers

Inscienceandtechnologyweoftenmeetcomplex

computations.Someofthemaretoolongandtoocomplicatedto

bedonebyhandinashorttime.Nowweuseelectroniccomputers

tofindsolutionstosuchproblems,sincetheygreatlyshortenthe

timeofcomplexcomputations.Ahigh-speedcomputerisableto

domillionsandmillionsofcalculationsinonesecond.

Electroniccomputercanalsostoreandre-useinformation.

Somecomputerscanstoremillionsofscientificdataand

“remember”whereeachoneis.Whensomeparticularinformation

isneeded,itcanbeobtainedquicklyfromthecomputer.Before

computersweredeveloped,onehandtospendalongtimetofind

theparticularinformationneeded.

Electroniccomputersdomanytasksbetter,fasterandmore

accuratelythanwecan,buttheywillneverbeabletoreplaceman.

Anelectroniccomputercandonothingifwedon'ttellitwhatto

do,whentodoitandhowtodoit.Thecomputermustbe

programmedbeforeitcanwork.

LessonSeventeen

Text

Carefulobservation

Theword“science“meansknowledge.Weusetheword,however,

inaspecialsense,tomeanknowledgeofthenatureofphysical

thingsandtheirmovementandchange.Thesunrisesmorningand

setsintheevening.Summerishotandwinteriscold.Living

thingsareborn,theygrow,anddie.Howdothesethingshappen?

Whydotheyhappenthisway?Sciencetriestofindreasonable

answerstosuchquestions.

Oneofthemostimportantactivitiesinscientificstudyiscareful

observation.Thereisastoryofaprofessorofmedicine.Whenhe

wasgivinghisfirstlessontohisstudents,hetoldthemthatifthey

wantedtobecomegooddoctors,thereweretwothingsofgreat

importance:onewastoobservecarefully,andtheotherwasnotto

bedisgustedatunpleasantthings.Infrontofhimwasaglassof

dirtywaterwithabadsmell.Hewentontosaythat,totestthem,

hewasgoingtoputafingerfirstintothewaterandthenintohis

mouth,andthathewantedthemtodoafterhimjustwhathedid.

Hedippedinafinger,andthenputafingerinhismouth.Inspite

ofthebadsmellofthewaterthestudentscameuponebyone,put

afingerinthewaterandthenintheirmouths.Atlasttheprofessor

said,UImustcongratulateyouonallhavingoneofthequalities

necessary,butonealone.Youdonotletunpleasantthingsdisgust

you,butneither,unfortunately,doyouobservecarefully,oryou

wouldhavenoticedthat,whileIputmysecondfingerinthewater,

itwasthethirdfingerthatIputinmymouth.^^Letthisstoryserve

toremindusoftheimportanceofcarefulobservation.Wemust

observewhatreallyhappens,andnotwhatwethinkisgoingto

happen.

ClassroomEnglish

Payattentiontoyourpronunciation.

Filreadthetextthroughonce.

Nowyouaregoingtoreadonebyone.

ReadingMaterial

Whydoesanapplefallfromatreetotheground?

In1642aboywasborninEngland.Hewastobecomeoneof

thegreatestscientistsintheworld.HisnamewasIsaacNewton.

Oneday,itissaid,whileNewtonwassittingunderatree,he

sawanapplefallfromit.Whydidtheappledothat?Whydidit

movetowardstheearth,andnottowardsthesky?Whenhehad

oncebeguntothinkaboutthis,hedidnotstopuntilhehad

reasoneditallout.Afteragreatdealofthinkinga