冀教版九年級全冊Unit 5 Lesson 29教案設計

Unit5LookintoScience

Lesson29

【教學目標】

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DNA的知識.

4.能夠理解課文內(nèi)容并回答課后的問題.

【教學內(nèi)容】

1.學會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.能夠運用下列句型：

(1)Ingeneral,blueprintisadrawingthatshowshowtoputahousetogetherwithmany

differentparts.

(2)Butbuildingalivingthingisfarmorecomplexthanbuildingahouse.

(3)YouhaveyourownuniqueDNA,butitrepeatspatternsfromyourparents'DNA.

(4)FromyourDNA,scientistscanidentifynotonlyyou,butalsopeoplewhoarerelatedto

you.

【教學重難點】

1.能夠正確應用本課的重點詞匯: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DNA的知識.

【教學思路】

思路一:以“DNA”為主題.通過展示圖片，詢問學生們”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?”引導學生們發(fā)現(xiàn)他們看起來相似的原因是由于DNA.通過設置學

生感興趣的話題導入新課，激發(fā)他們的學習興趣，調動他們的積極性和主動性.

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

文中的重點短語和句子，共同解決疑難.

【教學準備】

教師在課前設計教學PPT,準備錄音機和磁帶，多媒體等.

【教學過程】

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.

設計意圖:通過展示圖片，設置學生感興趣的問題,引出本課話題——DNA.激發(fā)了學生的學

習興趣.

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.

設計意圖:教師采用直接導入的方法,引出本課話題——DNA,使學生很直觀地進入本課的

學習，為下面的學習奠定基礎.

II.Presentation

TheteachershowsthenewwordsonPPT.Askstudentstotrytoreadthesewords.Thestudents

followtheteacherthreetimes.Thengivethestudentsfiveminutestorememberthewords.Let

studentsspellandreadthemonebyone.

設計意圖:教師以PPT的形式呈現(xiàn)本課中出現(xiàn)的生詞，領著學生們朗讀并記憶，為下面的課

文學習做好充分準備.

III.Reading

1.Readthetextaloud.

T:Boysandgirls,it'sourreadingtime.Pleasereadafterthevideoandyoushouldpaymore

attentiontoyourpronunciation.

設計意圖:讓學生大聲朗讀課文，對課文的意思有個大致的了解，對于培養(yǎng)學生的正確發(fā)音

以及培養(yǎng)學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，遠遠”，用來修飾形容詞和副詞的比較級，表示程度.

拓展:同樣用法的詞還有even"甚至"；rather”相當”;much".......得多"；alittle/bit”有點";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系.

besides可用作介詞，意為"除……之外”，表示同類事物間的疊加關系.

but可用作介詞，意為"除...之外"，常與no,all,every,each,none,nobody等詞連用,1ff時可

與except互換.

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

動詞用單數(shù);every強調整體概念，不能直接與of連用，指三者及三者以上中的每一個.

拓展:each可作形容詞，意為“每個的“，也可用作代詞，意為“每個”,each作形容詞時只能作定

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

each強調個體，可與of連用，指兩者及兩者以上中的每一個.

注意:“every/each+單數(shù)名詞+and+every/each+單數(shù)名詞”結構作主語時，謂語動詞用單數(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，還可作動詞，意為“擁有“，其

后賓語多表示房屋、土地或財產(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為及物動詞，意為”引起，導致，發(fā)生”，后面可接雙賓語，也可接動詞不定式作賓語補足

語.

拓展心use作名詞，意為”原因、起因”.指導致某種結果、造成一種事實的原因，通常與of連

用.

(6)Inthefuture,scientistsmightbeabletochangeyourDNA.

beablet。意為”能，會，表示通過努力而獲得的能力，強調結果，可用于各種時態(tài)，其后接動詞

原形.

(7)YouhaveyourownuniqueDNA,butitrepeatspatternsfromyourparents'DNA.

repeat為及物動詞，意為“重復，重述”，后接名詞或代詞作賓語.

parents，意為“父母親的”，是復數(shù)名詞的所有格形式.

(8)FromyourDNA,scientistscanidentifynotonlyyou,butalsopeoplewhoarcrelatedto

you.

identify為及物動詞，意為“確認，識別，鑒別”，后接名詞或代詞作賓語.

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

關的、相關的”.relate為動詞，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的定語從句的引導詞可用inwhich,或用

that,也可以不用引導詞.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+復數(shù)名詞”結構.其中定冠詞the也可使用形容詞性的物主代詞來代替.

設計意圖:學生是學習的主體，教師要努力調動學生學習的積極性和主動性,通過組內(nèi)合作

討論、探究，找出課文中的關鍵單詞、短語和句子，把所學的知識轉化為學習能力.

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.

設計意圖:鍛煉學生的口語表達與寫作能力,同時培養(yǎng)學生的合作意識.

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.同義句轉換

(1)BothyouandLindagiveusabigsurpris