流利说懂你英语Level4Unit2.docx

1、流利说懂你英语Level4Unit2Level4 Unit2 Part1 Listening - Extinction Events 1The Earth was formed about 4.6 billion years ago.The first life appeared about a billion years later.The first plants didnt appear until around 2 billion years ago.Until about 580 million years ago, life forms were small and microsc

2、opic.Since that time, life has evolved into many different types, or species.However, scientists estimate that more than 99% of them are now extinct.There have been several extinction events in the history of the Earth.In an extinction event many life forms, or species of life, die out.The causes of

3、 mass extinction events are unsolved mysteries.These events are not predictable and can happen at any time.Scientists think that some of them were started by asteroid impacts or volcanic eruptions.Events like these can change the global conditions that life depends on.One major extinction event happ

4、ened about 66 million years ago.That event may have been started by a large asteroid that hit the Earth.As a result, the dinosaurs and about half of all species on the planet died out.When the asteroid hit the earth, it started a chain of events.A chain of events is a series of events linked togethe

5、r, like a chain.This particular chain of events happened over a period of months and years.When the asteroid hit the Earth, it caused a huge cloud of dust to enter the atmosphere.This cloud of dust blocked the sun and darkened the Earth for many months.Without enough sunlight, plants and plant-eatin

6、g animals quickly died.With the deaths of so many plants and animals, the food chain collapsed.This led to the deaths of many more species.Mass extinction events have played an important part in the evolution of life.In fact, some extinction events have helped to accelerate evolution.For example, so

7、me mammals lived through the age of the dinosaurs, but they couldnt compete.When the dinosaurs were removed, the mammals were able to compete more successfully.Once they could compete, mammals evolved to a higher state.Without extinction events, perhaps we wouldnt be here today.Level4 Unit2 Part1 Li

8、stening - Extinction Events 2Scientists estimate that there have been at least 5 mass extinctions in the last 540 million years.They also believe that we have entered a new extinction event.Species are becoming extinct at a much faster rate than before.Instead of asteroids or volcanic eruptions, the

9、 current event is the result of human activities.Human activities, for example, have led to global warming.Global warming is the result of an increase in carbon gases in our atmosphere.These gases trap heat from the sun, so the Earth is getting warmer.As a result, sea levels are rising and weather p

10、atterns are changing.In addition, we humans are destroying the habitats of many plants and animals.Cutting down forests and polluting rivers destroys the habitats of many forms of life.There is no longer any doubt that this is happeningSpecies of life are disappearing at an increasing rate.Global te

11、mperatures are rising and weather patterns are changing.Scientists are warning us that fast action is necessary to save our future.If we dont act, we may go the way of the dinosaurs.(This new extinction event is caused by humans.)Level4 Unit2 Part1 Vocabulary - Body SystemsThe bodys circulatory syst

12、em includes the heart and blood vessels.The heart pumps blood to all parts of the body through a network of arteries and veins.The digestive system breaks down and absorbs food into the body.It supplies the energy that the body needs for growth and repair.After digestion, excess food is turned into

13、waste and eliminated from the body.The nervous system includes the brain, spinal cord and nerves.This is your bodys control system.It controls yourmuscles and organs, including your circulatory and digestive systems.The respiratory system includes the nose and lungs.It brings air and oxygen into the

14、 body and removes carbon dioxide.The lungs are where oxygen enters the bloodstream and carbon dioxide is removed.The immune system protects the body against infections and diseases.Sneezing and fever are examples of how the immune system works.If an infection invades the body, the immune system atta

15、cks it.(The blood vessels that carry oxygen-rich bloodfromthe heart are called arteries.)(The digestive system is where food is broken down and absorbed into the body.)(The nervous system regulates your heartbeat and digestion.)Level4 Unit2 Part1 Vocabulary - Great DiscoveriesThe controlled use of f

16、ire allowed people to cook food and survive in the colder climates.Fire provided light so that people could work andsocializefor longer hours.With the invention ofagriculture, people could grow food andsettle into communities.By growing food, people could spend less time hunting and more time for ot

17、her things such as art.Thedomesticationof animals allowed people to raise and use animals for food and work.By raising herds of animals such as sheep, humans had a regular supply of meat and clothing.The strength of animals such as horses andoxenwas used for work and transportation.The development o

18、ftools and machines has resulted in more efficientmanufacturing and construction.With better tools and machines, work can be done with fewer people and at much lower costs.The development of science and engineering has improved many things, including communications.With an understanding of electrici

19、ty, telephones and radios allow people to communicate over long distances.(Science and engineering have changed the way we communicate with each other.)(With the development of agriculture, people had more time for other activities.)(The use of machines has reduced the number of people needed to mak

20、e things.)Level4 Unit2 Part1 Dialogue - Smartphone AddictionI took a vacation last night.What are you talking about?Where did you take your vacation?I didnt go anywhere.I just spent an evening without my smartphone.How was it?It was great. I got a real magazine and read it with no interruption.It wa

21、s very peaceful.Yes, I havent done that in a long time.You know what?Im beginning to hate smartphones.Really? but you cant live without one, right?Yes, thats the problem.These things are changing the way people live.Yes, I just saw a documentary about that.A husband was complaining to his wife that

22、she was spending too much time on her smartphone.What happened? Did they get a divorce?You guessed it. In the end, they got a divorce.Its a bit ironic, dont you think?Smartphone were supposed to bring people together, but they are pulling people apart.Yes, you are right.Hey, just a minute. Ive got a

23、 message on my smartphone, and it cant wait.Level4 Unit2 Part1 Dialogue - Rude BossHey, wake up and get back to work.Whats wrong with you?Im on my break sir, and I have a bad headache.Well, we are not paying you to sleep.If youre going to sleep, sleep someplace else.Yes, sir, sorry, it wont happen a

24、gain.It had better not.Just a minute.Dont talk to me like that.What did you say?You hurt me. you dont have to treat people like that.Well, if you dont like it, I suggest you leave.OK, I will. Ive had enough of you.Ill get a job somewhere else.(The manager treats the employees in a threatening manner

25、.)(The employee treats the manager respectfully.)Level4 Unit2 Part2 Listening - Point of View 1This man is holding a piece of fruit in his hand.The piece of fruit is either an orange or an apple.We cant see which it is because we cant see inside the box.The probability that it is an orange is equal

26、to the probability that it is an apple.It may be an apple, and it may be an orange.Its got to be one or the other.It cant be anything else.Now lets look at it from the mans point of view.From his point of view, the probabilities are different.From his point of view, the probability that he has an or

27、ange is 100% or 0%.Thats because he knows what he has.For him there is no uncertainty.If he has an orange, the probability is 100%.If he doesnt have an orange, the probability is 0%.He either has it or he doesnt.From our point of view, the probability that he has an orange is 50%.From his point of v

28、iew, the probability that he has an orange is 100% or 0%.So the probability depends on your point of view.Level4 Unit2 Part2 Listening - Point of View 2People see things from different points of view.This often leads to arguments between people.Here are some examples.From this mans point of view, he

29、 is relaxing.He needs to relax because he has been working too hard.He hasnt been getting enough sleep.His wife sees things differently.She isnt aware of how hard he has been working.From her point of view, he is doing nothing.However, she knows what needs to be done around the house.It isnt fair th

30、at she has to work while he does nothing.When people see things from different points of view, they often come to different conclusions.These differences can cause real communication problems.Level4 Unit2 Part2 Vocabulary DisastersEarthquakes are caused by forces deep within the Earth.When the earth

31、 shakes, buildings can collapse and people can be buried inside.An explosion is a rapid, violent release of energy.Explosions can be caused by chemical reactions, such as inside an engine.A spark can ignite a mixture of gases, and release energy for good or destructive purposes.Accidents are often caused by people doing foolish things or by not being careful.One major cause of accidents is driving too fast.Accidents with fire can be very serious, and can result in very painful injuries.Epidemics are the rapid spread of a disease, such as the flu or ebola.Throughout hist