21世纪实用英语综合教程2教学课件U8B2.ppt

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1、UNIT 8Unit8.Objectives.Suggested Teaching Plan.Background Information.Class PresentationPreviewUNIT 8Preview This is the last unit of Book Two.In the Listening and Speaking section,you will learn how to ask for and give reasons.In the Reading and Writing section,you will read three passages about sc

2、ience and technology.Text A was written at the turn of the 21st century and the writer predicted the top five scientific developments of the coming century.Text B concerns issues of safety that must be guaranteed when the frontier of science and technology is being pushed back.Practical Reading is a

3、 form that people need to fill out upon arrival in the U.S.prev.UNIT 8.ObjectivesAfter studying this unit,the students are expected to be able toObj.master the basic language and skills necessary to ask for and give reasons;1.understand the main ideas of Texts A and B,and master the useful sentence

4、structures and words and expressions found in the exercises relevant to the texts;2.3.know how to use V-ing phrases,V-ed phrases and To V phrases as adverbials;4.know how to write an email;6.understand paragraph development(5).5.read a form that people need to fill out upon arrival in the U.S.UNIT 8

5、.Suggested Teaching PlanSuggested Time and Teaching Plan for Unit 8 Time Contents Plan 1)The Language for Asking For and Giving ReasonsGive a brief lead-in talk on the nature and uses of asking for and giving reasons;A.s.t.p.1The teacher begins with the Preview to make sure that the students have a

6、general idea of what this unit is all about.After that,the teacher activates listening and Speaking exercises as follows:2 periodsPreview Listening and SpeakingB.Present the necessary language by doing Exercise 1;UNIT 8C.Ask one student to read aloud the talk so students can check their completed an

7、swers;D.Organize an activity for Ex.2 that will reinforce the useful language students picked up in Ex.1.Time Contents Plan s.t.p.1.22)The Practice of Asking For and Giving ReasonsGo through the new words in the first conversation in Ex.3;A.B.Have the students listen to the conversation twice and fi

8、ll in the blanks with the missing words;C.Ask them to answer the questions about the conversation;UNIT 8D.Tell them to look for the language used to asking for and giving reasons;Time Contents Plan s.t.p.2Ask the students to role-play the conversation;Have them listen to the second conversation twic

9、e and complete the short passage accordingly;F.E.Suggest they discuss each of their completed answers in order to gain a better understanding of the conversation;G.Now,have them listen to the conversation again and complete the form as the speaker recounts it;H.Afterwards,have them check their respo

10、nses by acting out the conversation;I.UNIT 8Time Contents Plan s.t.p.33)Listening PracticeBefore ending,the teacher tells the students to do Ex.5-10 as their assignment to review the functional and notional language picked up in the Listening and Speaking section.The teacher also tells them that the

11、y should be prepared to answer the questions in Exercise 9 and give an oral presentation in class when they next meet.Organize a unique classroom activity for Ex.4 that will reinforce the useful language students picked up earlier in the unit.J.UNIT 83 periods Review of the listening and speaking sk

12、ills the studentshave learnedThe teacher begins with a review of the functional and notional language the students picked up in the previous classes.The teacher asks several students to answer the questions in Ex.9 of the Listening and Speaking section,and invites a few to share with their classmate

13、s their opinions on the topic “It is more important to raise questions than to answer them.”Then,the teacher turns to the Reading and Writing section.(These activities should be completed in 15 minutes.)s.t.p.4Time Contents Plan UNIT 81)StarterAfter a brief explanation of the instructions,the teache

14、r A.gives the students a few minutes to think about the questions in the starter;s.t.p.5Time Contents Plan B.asks some students to answer the questions.2)Text AA.The teacher lets the students answer the text-related questions,helps them identify the main idea of each paragraph,and analyzes some diff

15、icult sentences and some languageText A&text-related exercises UNIT 8B.guides the students through the exercises,focusing on certain items or leaving some exercises as the students homework according to the students different levels of English(one period).s.t.p.81 period Grammar Review1)Grammar Revi

16、ewThe teacher talks about the use of V-ing phrases,V-ed phrases and To V-phrases as adverbials,and at the same time asks the students to do the grammar exercises in class.Time Contents Plan points while discussing the whole text with the students(one and a half periods);UNIT 8s.t.p.9Practical Writin

17、g2)Practical WritingThe teacher explains to the students how to write an email by doing Ex.12 of Practical Writing,and then requires the students to do Ex.13 and Ex.14 after class.Time Contents Plan UNIT 8s.t.p.102 periods Text B,&Text-related exercises 1)Text BWhile discussing the text with the stu

18、dents,the teacher calls on them to pay attention to the structure of the paragraphs of the text,introducing briefly the concept of the topic sentence.Ex.16 and Ex.17 can be done either in or after class.2)Practical ReadingThis part should either be read by the students themselves as their homework o

19、r done in class.Time Contents Plan Practical ReadingUNIT 8s.t.p.11Basic Reading Skills3)Basic Reading SkillsThe teacher explains to the students paragraph development(5),and asks them to do the exercises in Basic Reading Skills.Time Contents Plan UNIT 8.Background InformationJames TrefilOriginal Tex

20、t of “The Top 5 Scientific Breakthroughs of the 21st Century”BIModern Science(20th century)Three Mile IslandThe Chernobyl AccidentRadiation sickness Soviet Union and RussiaUNIT 8BI-JTJames Trefil As an award-winning author and physicist,James Trefil has written more than 25 books on a range of scien

21、ce topics.Hes a contributor to National Public Radio and Smithsonian Magazine,and a physics professor at Virginias George Mason University,U.S.A.UNIT 8Original Text of “The Top 5 Scientific Breakthroughs of the 21st Century”The 20th century produced scientific and technological change at a dizzying

22、pace-greater than in any other century in history.But the 21st century,the dawn of the new millennium,may well see even more dramatic change driven by advances in science and technology.On these pages are my predictions for the top scientific developments well see in the next 100 years,in the order

23、I think theyll happen.BI-OT1(其中提及了作者进行预测的根据其中提及了作者进行预测的根据)James TrefilUNIT 8BI-OT21.Well know where we came from Why does the universe exist?To put it another way,why is there something instead of nothing?Since the 1920s,scientists have known the universe is expanding,which means it must have starte

24、d at a definite time in the past.They even have developed theories that give a detailed picture of the evolution of the universe from the time it was a fraction of a second old to the present.Over the next couple of decades,these theories will be refined by data from extraordinarily powerful new tel

25、escopes and advances in our understanding of how matter behaves at the unfathomably high temperatures and pressures of the early universe.UNIT 8BI-OT2 Margaret Geller of the Harvard-Smithsonian Center for Astrophysics,a pioneer in exploring the structure of the universe,believes that“by 2100,we will

26、 have a complete map of all the galaxies in the visible universe.”Considering that the first primitive maps of North America(produced by explorers who followed Columbus)appeared only 500 years ago,a mere century to map every galaxy within 15 billion light-years of Earth seems a breathtaking accompli

27、shment.UNIT 8BI-OT32.Well crack the genetic code and conquer cancer In 19th-century operas,when the heroine coughs in the first act,the audience knows she will die of tuberculosis in Act 3.But thanks to 20thcentury antibiotics,the once-dreaded,once-incurable disease now can mean nothing more serious

28、 than taking some pills.As scientists learn more about the genetic code and the way cells work at the molecular level,many serious diseases cancer,for one will become less threatening.Using manufactured“therapeutic”viruses,doctors will be able to replace cancer-causing damaged DNA with healthy genes

29、,probably administered by a pill or injection.UNIT 8BI-OT3 French Anderson of the University of Southern California Medical School,who did the first gene-therapy treatment on a human,predicts that“in 15 or 20 years,the majority of diseases will be treatable in this way.”By the end of the next centur

30、y,people will look at our fear of cancer the way we now look at the operatic fear of TB:as a quaint relic of an immature technology.UNIT 8BI-OT43.Well live longer(120 years?)If the normal aging process is basically a furious,invisible contest in our cells a contest between damage to our DNA and our

31、cells ability to repair that damage then 21st-century strides in genetic medicine may let us control and even reverse the process.Experts in this field distinguish between increasing longevity(extending the average life span now 76.5 years in the United States as we have been doing for centuries)and

32、 increasing the maximum possible life span(which seems to be about 120 years).No doubt we can achieve the first,but experts are reluctant to speculate about the second.Says Rita Effros of the UCLA School ofUNIT 8BI-OT4Medicine,a leading researcher on aging and the immune system:“I think 120 years of

33、 good health is enough for anyone.”So before we push scientists to do more,consider:Do we really want to live in a world where no one grows old and(presumably)few children are born because the planet can hold only so many people?Where would new ideas come from?What would we do with all that extra ti

34、me?And would you really want to be a deputy assistant manager for 500 years?UNIT 8BI-OT64.Well“manage”Earth In the next millennium,well stop talking about the weather and do something about it.David Tilman of the University of Minnesota,a pioneer in developing and testing ecological theories,says,“T

35、he worlds ecosystems are incredibly complex,and the job of understanding them is made harder by the fact that they are being changed by the influence of human beings.”As we build bigger and faster computers,however,the mystery and unpredictability will start to fade.UNIT 8BI-OT6 Well gradually learn

36、 how to predict the effects of human activity on the Earth,its climate and its ecosystems.And with that knowledge will come an increasing willingness to use it to manage the workings of our planet.Earth will be managed,like a farm or a game preserve.The Dutch have been doing this sort of thing on a

37、smaller scale for centuries in managing their system of dikes.I see no reason humanity organized in a global village cant do the same.UNIT 8BI-OT55.Well have a brain“road map”This is the real“final frontier”of the 21st century:The brain is the most complex system we know.It contains about 100 billio

38、n neurons(roughly the number of stars in the Milky Way),each connected to as many as 1,000 others.Early in the next century,we will use advanced forms of magnetic resonance imaging to produce detailed maps of the neurons in operation.Well be able to say with certainty which ones are working when you

39、 read a word,when you say a word,when you think about a word,and so on.UNIT 8BI-OT7 Steven Pinker of the Massachusetts Institute of Technology,noted psychologist and author of the book How the Mind Works,predicts that in the next century“well learn a lot about things we dont understand today:human e

40、motions,social relationships,reasoning and decision-making.”Well see new treatments for specific mental conditions(as todays Prozac treats depression).Well develop medicines that enhance mental functions like the steroids athletes use to promote muscle growth,but without the harmful side effects.So

41、with this fifth prediction we come full circle,and realize that the most difficult thing to understand in the universe may be the 3-pound organ we carry around in our skulls the organ that allows us to understand the universe in the first place.UNIT 8BI-MS1Modern Science(20th century)In the 20th cen

42、tury,scientists achieved spectacular advances in the fields of genetics,medicine,social sciences,technology,and physics.1.Genetics At the beginning of the 20th century,the life sciences entered a period of rapid progress.Mendels work in genetics was rediscovered in 1900,and by 1910 biologists had be

43、come convinced that genes are located in chromosomes,the threadlike structures that contain proteins and deoxyribo-nucleic acid(DNA).During the 1940s American biochemists discovered that DNA taken from one kind of bacterium could influence the characteristics of another.From these experiments,it bec

44、ame clear that DNA is the chemical that makes up genes and thus the key to heredity.UNIT 8BI-MS2 After American biochemist James Watson and British biophysicist Francis Crick established the structure of DNA in 1953,geneticists became able to understand heredity in chemical terms.Since then,progress

45、 in this field has been astounding.Scientists have identified the complete genome,or genetic catalog,of the human body(see Human Genome Project).In many cases,scientists now know how individual genes become activated and what effects they have in the human body.Genes can now be transferred from one

46、species to another,side-stepping the normal processes of heredity and creating hybrid organisms that are unknown in the natural world(see Transgenic Organism).UNIT 8BI-MS32.Medicine At the turn of the 20th century,Dutch physician Christiaan Eijkman showed that disease can be caused not only by micro

47、organisms but by a dietary deficiency of certain substances now called vitamins.In 1909 German bacteriologist Paul Ehrlich introduced the worlds first bactericide,a chemical designed to kill specific kinds of bacteria without killing the patients cells as well.Following the discovery of penicillin i

48、n 1928 by British bacteriologist Sir Alexander Fleming,antibiotics joined medicines chemical armory,making the fight against bacterial infection almost a routine matter.Antibiotics cannot act against viruses,but vaccines have been used to great effect to prevent some of the deadliest viral diseases.

49、Smallpox,once a worldwide killer,was completely eradicated by the late 1970s,and in the United States the number of polio cases dropped from 38,000 in the 1950s to less than 10 a year by the 21st century.UNIT 8BI-MS4 By the middle of the 20th century scientists believed they were well on the way to

50、treating,preventing,or eradicating many of the most deadly infectious diseases that had plagued humankind for centuries.But by the 1980s the medical communitys confidence in its ability to control infectious diseases had been shaken by the emergence of new types of disease-causing microorganisms.New