Unit5LookintoScience

Lesson29

【教學(xué)目標(biāo)】

1.記憶單詞DNA,blueprint,general,complex,twin,repeat,pattern,identify,related,grandson,

granddaughter,instruction;短語ingeneral,exceptfor,erelatedto,billionsof.

2.掌握重點(diǎn)句型：

(1)Ingeneral,blueprintisadrawingthatshowshowtoputahousetogetherwithmany

differentparts.

(2)Butbuildingalivingthingisfarmorecomplexthanbuildingahouse.

(3)YouhaveyourownuniqueDNA,butitrepeatspatternsfromyourparents'DNA.

(4)FromyourDNA,scientistscanidentifynotonlyyou,butalsopeoplewhoarerelatedto

you.

3.能夠用英語向他人介紹自己所知道的有關(guān)DNA的知識(shí).

4.能夠理解課文內(nèi)容并回答課后的問題.

【教學(xué)內(nèi)容】

1.學(xué)會(huì)并能正確使用單詞及短語:DNA,blueprint,general,complex,twin,repeat,pattern,

identify,related,grandson,granddaughter,instruction,ingeneral,exceptfor,berelatedto,billions

of.

2.能夠運(yùn)用下列句型：

(1)Ingeneral,blueprintisadrawingthatshowshowtoputahousetogetherwithmany

differentparts.

(2)Butbuildingalivingthingisfarmorecomplexthanbuildingahouse.

(3)YouhaveyourownuniqueDNA,butitrepeatspatternsfromyourparents'DNA.

(4)FromyourDNA,scientistscanidentifynotonlyyou,butalsopeoplewhoarerelatedto

you.

【教學(xué)重難點(diǎn)】

1.能夠正確應(yīng)用本課的重點(diǎn)詞匯:DNA,blueprint,general,complex,twin,repeat,pattern,

identify,related,grandson,granddaughter,insiruciion;掌握短語ingeneral,exceptfor,berelatedto,

billionsof.

2.能夠用英語向他人介紹自己所知道的有關(guān)DNA的知識(shí).

【教學(xué)思路】

思路一:以“DNA”為主題.通過展示圖片，詢問學(xué)生們”他們看起來一樣嗎?為什么一樣?他們

看起來不同嗎?為什么不同?”引導(dǎo)學(xué)生們發(fā)現(xiàn)他們看起來相似的原因是由于DNA.通過設(shè)置學(xué)

生感興趣的話題導(dǎo)入新課，激發(fā)他們的學(xué)習(xí)興趣，調(diào)動(dòng)他們的積極性和主動(dòng)性.

思路二:以“DNA”為主題.通過師生對(duì)話，直接導(dǎo)入本課話題DNA.通過小組合作探究，找出

文中的重點(diǎn)短語和句子，共同解決疑難.

【教學(xué)準(zhǔn)備】

教師在課前設(shè)計(jì)教學(xué)PPT,準(zhǔn)備錄音機(jī)和磁帶，多媒體等.

【教學(xué)過程】

I.Leadin

Leadingin情景1

ThisittheshaoeofDNADoyou

tNnkiT*

T:Hello,class.TodaywelllearnLesson29.(TheteachershowstwopicturesonPPT.)Please

lookatthepictures.Aretheylookthesame?Aretheredifferencesbetweenthem?

SI:...

T:Whydosomestudentslookdifferent?Andwhydocousinslooksimilar?

Ss:BecauseofDNA.

T:Welldone.Nowlet*slearnLesson29:DNA—TheStoryofYou.

設(shè)計(jì)意圖:通過展示圖片，設(shè)置學(xué)生感興趣的問題,引出本課話題——DNA.激發(fā)了學(xué)生的學(xué)

習(xí)興趣.

Leadingin情景2

T:Goodmorning/afternoon,everyone.WhatisDNA?WhatdoesDNAstandfor?

SI:DNAissomethingthatalllivingthingshave.

S2:DNAcarriesthegeneticinformationthatmakeseverylivingthingwhatitis.

T:Verygood.DNAisshortforthefullscientificterm"deoxyribonucleicacid".That'shardto

say.DNAismucheasier.EverylivingthinghasitsownDNA.DNAholdstheinformationand

instructionsforcreatingalivingthing.Forexample,Ihavestraightblackhairbecausepartofthe

instructionsinmyDNAwastogivemestraightblackhair.Mygrandmotherhasthesamestraight

blackhair.Ihavepartofmygrandmother'sDNA.

設(shè)計(jì)意圖:教師采用直接導(dǎo)入的方法,引出本課話題——DNA,使學(xué)生很直觀地進(jìn)入本課的

學(xué)習(xí)，為下面的學(xué)習(xí)奠定基礎(chǔ).

II.Presentation

TheteachershowsthenewwordsonPPT.Askstudentstotrytoreadthesewords.Thestudents

followtheteacherthreetimes.Thengivethestudentsfiveminutestorememberthewords.Let

studentsspellandreadthemonebyone.

設(shè)計(jì)意圖:教師以PPT的形式呈現(xiàn)本課中出現(xiàn)的生詞，領(lǐng)著學(xué)生們朗讀并記憶，為下面的課

文學(xué)習(xí)做好充分準(zhǔn)備.

III.Reading

1.Readthetextaloud.

T:Boysandgirls,it'sourreadingtime.Pleasereadafterthevideoandyoushouldpaymore

attentiontoyourpronunciation.

設(shè)計(jì)意圖:讓學(xué)生大聲朗讀課文，對(duì)課文的意思有個(gè)大致的了解，對(duì)于培養(yǎng)學(xué)生的正確發(fā)音

以及培養(yǎng)學(xué)生的語感都有重要作用.

2.Carefulreading.

T:Boysandgirls,nowthistime,I'llmaketheexercisealittlemoredifficult.Readthelesson

againandanswerthequestions.

ShowLet'sDoIt!

Readthelessonandanswerthequestions.

(1)Whatisablueprint?

(2)Whichismorecomplex,buildingalivingthingorbuildingahouse?

(3)DosometwinshavethesameDNA?

(4)IsitpossibletochangeyourDNA?

(5)WhoseDNAisrelatedtoyours?

Keys:

(DAblueprintisadrawingthatshowshowtoputahousetogetherwithmanydifferentparts.

living為形容詞，意為”活著的，活的”，常作定語.

far為副詞，意為“非常，遠(yuǎn)遠(yuǎn)”，用來修飾形容詞和副詞的比較級(jí)，表示程度.

拓展:同樣用法的詞還有even"甚至"；rather”相當(dāng)”;much".......得多"；alittle/bit”有點(diǎn)";a

lot"......得多”等等.

(4)Exceptforsometwins,everylivingthinghasitsownuniqueDNA.

exceptfor意為”除……之外”，它要求排除的是不同類的.

辨析：exceptfor,except,besides,but

exceptfor意為“除了”，表示對(duì)主體的肯定和局部的否定，用于不同類的事物間.

except可用作介詞，意為“除了……之外”，表示同類事物間的排除關(guān)系.

besides可用作介詞，意為"除……之外”，表示同類事物間的疊加關(guān)系.

but可用作介詞，意為"除...之外"，常與no,all,every,each,none,nobody等詞連用,1ff時(shí)可

與except互換.

every為形容詞，意為“每一的，每一個(gè)的”，其后接單數(shù)名詞;"every+單數(shù)名詞”作主語時(shí)，謂語

動(dòng)詞用單數(shù);every強(qiáng)調(diào)整體概念，不能直接與of連用，指三者及三者以上中的每一個(gè).

拓展:each可作形容詞，意為“每個(gè)的“，也可用作代詞，意為“每個(gè)”,each作形容詞時(shí)只能作定

語,其后接單數(shù)名詞;”each+單數(shù)名詞”或each作主語時(shí)，謂語動(dòng)詞用單數(shù)；

each強(qiáng)調(diào)個(gè)體，可與of連用，指兩者及兩者以上中的每一個(gè).

注意:“every/each+單數(shù)名詞+and+every/each+單數(shù)名詞”結(jié)構(gòu)作主語時(shí)，謂語動(dòng)詞用單數(shù)形

式.

own作形容詞，意為“自己的“，位于物主代詞或名詞所有格之后，還可作動(dòng)詞，意為“擁有“，其

后賓語多表示房屋、土地或財(cái)產(chǎn)等，其名詞形式為owner,意為“物主”.

(5)SomehealthproblemscanbecausedbyproblemsinyourDNA.

health為不可數(shù)名詞，意為“健康”，常構(gòu)成短語ingood/badhealth,意為“健康/不健康”.

拓展：

heakhy為形容詞，意為“健康的”;unhealthy意為“不健康的”,keep/slayhealthy意為”保持健康

healthily為副詞，意為“健康地，eathealthily意為"吃得健康

cause為及物動(dòng)詞，意為”引起，導(dǎo)致，發(fā)生”，后面可接雙賓語，也可接動(dòng)詞不定式作賓語補(bǔ)足

語.

拓展心use作名詞，意為”原因、起因”.指導(dǎo)致某種結(jié)果、造成一種事實(shí)的原因，通常與of連

用.

(6)Inthefuture,scientistsmightbeabletochangeyourDNA.

beablet。意為”能，會(huì)，表示通過努力而獲得的能力，強(qiáng)調(diào)結(jié)果，可用于各種時(shí)態(tài)，其后接動(dòng)詞

原形.

(7)YouhaveyourownuniqueDNA,butitrepeatspatternsfromyourparents'DNA.

repeat為及物動(dòng)詞，意為“重復(fù)，重述”，后接名詞或代詞作賓語.

parents，意為“父母親的”，是復(fù)數(shù)名詞的所有格形式.

(8)FromyourDNA,scientistscanidentifynotonlyyou,butalsopeoplewhoarcrelatedto

you.

identify為及物動(dòng)詞，意為“確認(rèn)，識(shí)別，鑒別”，后接名詞或代詞作賓語.

berelatedto意為”和……有聯(lián)系，和……有關(guān)，與……有親戚關(guān)系”.related為形容詞，意為”有

關(guān)的、相關(guān)的”.relate為動(dòng)詞，意為"把……聯(lián)系起來”，常與to或with搭配.

(9)YourDNAhasbillionsofinstructionsthatexplainwhyyouarethewayyouare.

本句句末的youare是theway的定語從句.theway的定語從句的引導(dǎo)詞可用inwhich,或用

that,也可以不用引導(dǎo)詞.way在本句中意為“情況、狀態(tài)二

(10)It'soneofthemostamazingthingsontheearth!

oneofthemostamazingthings意為"最令人驚奇的事情之一"，為"oneofthe+形容詞的最高

級(jí)+復(fù)數(shù)名詞”結(jié)構(gòu).其中定冠詞the也可使用形容詞性的物主代詞來代替.

設(shè)計(jì)意圖:學(xué)生是學(xué)習(xí)的主體，教師要努力調(diào)動(dòng)學(xué)生學(xué)習(xí)的積極性和主動(dòng)性,通過組內(nèi)合作

討論、探究，找出課文中的關(guān)鍵單詞、短語和句子，把所學(xué)的知識(shí)轉(zhuǎn)化為學(xué)習(xí)能力.

IV.Task

1.ShowLet'sDoIt!

IsitagoodideatochangetheDNAofthefoodweeat?Somepeoplesaydoingthismakesour

foodbetter.Othersthinkit'stoodangerous.SearchtheInternetforinformationandwritedownyour

ideas.

2.HavethestudentsconsiderthequestionsinLet'sDoIt!No.4.

3.Havethemcompletethistaskandresearchgeneticallymodifiedfood.Theirresearchshould

answerthefollowingquestions:

Doyouthinkit'sagoodideatochangetheDNAofthefoodweeat?Whyorwhynot?

Whataresomeofthepositivesofgeneticallymodifiedfood?

Whataresomeofthenegativesofgeneticallymodifiedfood?

4.Havethegroupspresenttheirresearchintheformofacommercialthatiseitheradvertising

thecontinuationofgeneticallymodifiedfoodortheendofit.

設(shè)計(jì)意圖:鍛煉學(xué)生的口語表達(dá)與寫作能力,同時(shí)培養(yǎng)學(xué)生的合作意識(shí).

V.Practice

1.ShowLet,sDoIt!No.2.

Fillintheblankswiththephrasesinthebox.

ingeneral,exceptfor,notonly.,butalso,relatedto,evenif,thesame...as...

(1)Yourhomeworkisquitegoodafewspellingmistakes.

(2)theyoungtheoldlikepopmusic.

(3)Kate'shairiscolorhersister's.

(4),womenlivelongerthanmen.

(5)manydifficultiesremain,wecanovercomethem.

(6)Iswealthhappiness?

2.Completethepassagewiththesentencesinthebox.

ChangingDNA

DoyouknowDNAcanbechanged?Haveyoueverseenapigwithadog'sbody?Ofcoursenot!

Pigsanddogscan'thavebabiestogether.butnow.scientistscandoit.Scientistscantake

DNAfromonekindofanimalandputitintoanotherkindofanimal.Theycandesignnewplantsby

combiningtheDNAofotherplants.Somescientistsareworried.Theysayweneedtoknow

moreaboutDNAbeforewestartchangingit.Butwhatiftheplantsarebadforhumans,too?

A.TheirDNAcan'tcombine.

B.Wecanmakeplantsthatarebadforpests.

C.TheycanevencombinetheDNAofaplantandananimal.

3.同義句轉(zhuǎn)換

(1)BothyouandLindagiveusabigsurpris