懂你英语L4U2

1、【精品文档】如有侵权，请联系网站删除，仅供学习与交流懂你英语L4U2.精品文档.懂你英语L4-Unit2 1 Extinction EventsLevel4 Unit2 1 Listening Extinction EventsThe Earth was formed about 4.6 billion years ago.The first life appeared about a billion years later.The first plants didn't appear until around 2 billion years ago. Until about

2、 580 million years ago, life forms were small and microscopic. 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 even

3、t many life forms, or species of life, die out. The causes of 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

4、 conditions that life depends on.One major extinction event happened 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 cha

5、in of events. A chain of events is a series of events linked together, 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

6、 Earth for many months. Without enough sunlight, plants and plant-eating 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,

7、some extinction events have helped to accelerate evolution. For example, some mammals lived through the age of the dinosaurs, but they couldn't compete. When the dinosaurs were removed, the mammals were able to compete more successfully. Once they could compete, mammals evolved to a higher state

8、. Without extinction events, perhaps we wouldn't be here today.Scientists 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. Instea

9、d of asteroids or volcanic eruptions, the 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

10、 result, sea levels are rising and weather patterns 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 happening. Species of life

11、are disappearing at an increasing rate. Global temperatures are rising and weather patterns are changing. Scientists are warning us that fast action is necessary to save our future. If we don't act, we may go the way of the dinosaurs. (This new extinction event is caused by humans.)Level4 Unit2

12、1 VocabularyBody SystemsThe body's circulatory system includes the heart and blood vessels. The heart pumps blood to all parts of the body through a network of arteries and veins. (The blood vessels that carry oxygen-rich bloodfrom the heart are called arteries.)The digestive system breaks down

13、and absorbs food into the body. It's supplies the energy that the body needs for growth and repair. After digestion, excess food is turned into waste and eliminated from the body. (The digestive system is where food is broken down and absorbed into the body.)The nervous system includes the brain

14、,spinal cord and nerves. This is your body's control system. It controls your muscles and organs, including your circulatory and digestive system. (The nervous system regulates your heartbeat and digestion.)The respiratory system includes the nose and lungs. It brings air and oxygen into the bod

15、y 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

16、cks it.Great DiscoveriesThe controlled use of fire allowed people to cook food and survive in the colder climates. Fire provided light so that people could work andsocialize for longer hours.With the invention of agriculture, people could grow food andsettle into communities. By growing food, people

17、 could spend less time hunting, and more time for other things such as art. (With the development of agriculture, people had more time for other activities.)The domestication of animals allowed people to raise and use animals for food and work. By raising herds of animals such as sheep, humans had a

18、 regular supply of meat and clothing. The strength of animals such as horses andoxen was used for work and transportation.The development of tools and machines has resulted in more efficient manufacturing and construction. With better tools and machines, work can be done with fewer people and a

19、t much lower costs. (The use of machines has reduced the number of people needed to make things.)The development of science and engineering has improved many things, including communications. With an understanding of electricity, telephones and radios allow people to communicate over long distances.

20、 (Science and engineering have changed the way we communicate with each other.)Level4 Unit2 Part1 DialogueSmartphone AddictionI took a vacation last night.What are you talking about?Where did you take your vacation?I didn't go anywhere.I just spend an evening without my smartphone.How was it?It

21、was great. I got a real magazine and read it with no interruption.It was very peaceful.Yes, I haven't done that in a long time.You know what?I'm beginning to hate smartphones.Really? but you can't live without one, right?Yes, that's the problem.These things are changing the way peopl

22、e live.Yes, I just saw a documentary about that.A husband was complaining to his wife that 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.It's a bit ironic, don't you think?Smartphone were supposed to brin

23、g people together, but they are pulling people apart.Yes, you are right.Hey, just a minute. I've got a message on my smartphone, and it can't wait.Rude BossHey, wake up and get back to work.What's wrong with you?I'm on my break sir, and I have a bad headache.Well, we are not paying y

24、ou to sleep.If you're going to sleep, sleep someplace else.Yes, sir, sorry, it won't happen again.It had better not.Just a minute.Don't talk to me like that.What did you say?You hurt me. you don't have to treat people like that.Well, if you don't like it, I suggest you leave.OK,

25、I will. I've had enough of you.I'll get a job somewhere else.(The manager treats the employees in a threatening manner.)(The employee treats the manager respectfully.)懂你英语L4-Unit2 2 Point of viewLevel4 Unit2 Part2 ListeningPoint of viewThis man is holding a piece of fruit in h

26、is 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 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 anyth

27、ing 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 orange 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

28、 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 view, the probability that he has an orange is 100% or 0%. So the probability depends on your point of view.People se

29、e things from different points of view. This often leads to arguments between people. Here are some examples. From this mans point of view, he 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 h

30、ow 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 that she has to work while he does nothing.When people see things from different points of view, they often come to different conclusions. These differenc

31、es can cause real communication problems.Level4 Unit2 Part2 VocabularyDisastersEarthquakes are caused by forces deep within the earth. When the earth shakes, buildings can collapse and people can be buried inside.An explosion is a rapid, violent release of energy. Explosions can be caused by chemica

32、l reaction, 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 seriou

33、s and can result in very painful injuries.Epidemics are the rapid spread of a disease, such as the flu or Ebola. Throughout history epidemics have killed millions of people.Storms are caused by changes in the atmosphere resulting in high winds and heavy rain. Thunderstorms are caused by electric cha

34、rges in the atmosphere that produce lightning, which can cause forest fires. Some storms cause flooding and major damage to homes and cities.ReligionsFollowers of the Islam religion are called Muslims. These Muslims are praying inside a mosque. Muslims are called to prayer 5 times a day, beginning j

35、ust before sunrise.Christianity is based on the teachings of Jesus Christ who lived more than 2000 years ago. Christians believe that Jesus is the son of god. Christians often gather in churches or cathedrals to worship.Followers of Judaism are called Jews. These Jews are meeting inside a synagogue,

36、 which is a place of worship and study. Judaism was founded over 35 hundred years ago in the middle east. Judaism is based on the teachings of Moses, who they believe is the most important prophet.Buddhism began in India and is based on the teachings of the Buddha. The religion is about 25 hundred y

37、ears old. Some Buddhists practice a form of meditation in which they empty their minds of any thought.Hinduism is the worlds third most popular religion and is the main religion of India. Hinduism has no founder and is a mixture of many beliefs. Some Hindus believe in the cycle of birth, life, death

38、 and rebirth.Level4 Unit2 Part2 DialogueMissing AircraftDo you have any more information about the location of the missing aircraft?No, we dont. The only information we have is that it disappeared.What about the last communication with the aircraft?The last communication was about 15 minutes before

39、it disappeared.Was there anything unusual in the communication?No, there wasn't anything unusual.Nothing pointed to any kind of problem.Anyway, we are confident that we will find it.Its a large aircraft so it shouldnt be difficult to find.How many countries are helping with the search?Right now,

40、 we have search teams from 3 countries starting the search.Its a big area to search, so can you give us an estimate about how long it will take?Yes, its a big area, so it might take a long time.But we wont give up.We will search until we find it.Have they found the wreckage yet?What are you talking

41、about?You know, the airplane that disappeared last year.Oh, yes, now I know what you are referring to.Yes, they found some piece of it.What about the black boxes?No, they still havent found the black boxes.Its hard to believe they still dont know what happened.Perhaps theyll never know, especially i

42、f they dont find the black boxes.Whatever happened to it, there is no good reason why a modern airline is allowed to disappear.I agree with you.懂你英语L4-Unit2 3Level4 Unit2 Part3 Listening AlcatrazAlcatraz is a small island in San Francisco Bay, 1.5 miles from San Francisco. From Alcatraz, you ca

43、n see the famous Golden Gate Bridge. Alcatraz is also famous and is now a major tourist attraction. Tourists can reach the island by boat from the city.Alcatraz has often appeared in movies, including "Escape from Alcatraz" which was made in 1979. One reason its famous is because it used t

44、o be a prison, a very special prison. It was designed for prisoners who were causing trouble in other prisons, such as trying to escape. It was a maximum security prison, so escape was almost impossible. The waters around it are cold, and only very strong swimmers can swim from the island to San Fra

45、ncisco.The first group of prisoners arrived in 1934. There were 137 prisoners, including bank robbers and murderers. They came by train from another prison in the state of Kansas. During that trip, there was heavy security. The prisoners were under guard and handcuffed. Nobody wanted them to escape.

46、The prison was designed to hold up to 336 prisoners. However, the average population was only about 270. Although there were several notorious inmates, such as Al Capone, most of the inmates were not well-known. Many had tried to escape from other prisons or were considered violent. If a man did not

47、 behave at another prison, he could be sent to Alcatraz. At Alcatraz there was just one inmate in each prison cell.Prison life at Alcatraz was highly structured and boring. It was designed to teach prisoners to follow rules. They had four rights: food, clothing, shelter, and medical care. Everything

48、 else was a privilege that had to be earned. Privileges included working, visits from family members, and access to the prison library. There were also activities such as painting and music. Once a prisoner showed that he could follow the rules, he could be transferred back to another prison to fini

49、sh his sentence.Alcatraz was used as a prison for 29 years. During that time, no prisoner escaped successfully. There were 14 escape attempts, involving 36 prisoners. Twenty-three were caught alive, and six were shot and killed. Two men tried to escape twice. Two drowned and five were listed as miss

50、ing and presumed drowned. The most violent escape attempt occurred on May 2, 1946 when six prisoners tried to escape. That event is called the "Battle of Alcatraz."While it was in use, Alcatraz held some of the most notorious criminals in American history, such as Al Capone. Al Capone was

51、a crime boss who built his career in Chicago. The prison was finally closed in 1963. It was closed because it was too expensive to operate.Level4 Unit2 Part2 VocabularyGraphs & chartsA bar graph uses rectangular bars of different lengths to show and compare data. The lengths of the bars are prop

52、ortional to the values they represent. The bars can be vertical, up and down, or horizontal.A circle graph, often called a pie graph, is shaped like a circle. It is divided into segments that look like pieces of a pie. Percentages are used to compare the segments, which are ordered from biggest to s

53、mallest.Line graphs are used to show the relationship between two variables, such as time and distance. These variables are plotted on 2 axes, the X axis and the Y axis. The X axis often shows time, while the Y axis shows how quantities, such as distance, temperature, or profits change with time.A f

54、lowchart is a type of graph that shows how a process or a project flows from start to finish. A flow chart consists of start points, inputs, outputs and decision points.An organizational chart or org chart show the structure of a company. It shows how people and departments within a company are connected. It defines the roles and responsibilities of people and departments within a company.Legal TermsLaws are rules that people are supposed to follow. A system of laws governs the behavior of people