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Level4 Unit2 1 Listening?

Extinction Events

The Earth was formed about

billion years

first life appeared about a billion years

first plants didn't appear

until around 2 billion years ago. Until about 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 event 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 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 chain 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

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, 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. 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. Instead 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 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 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 1 Vocabulary

Body Systems

The 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 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,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 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 attacks it.

Great Discoveries

The 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

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 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 at 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. (Science

and engineering have changed the way we communicate with each other.)

Level4 Unit2 Part1 Dialogue

Smartphone Addiction

I 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 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 people 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 bring 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 Boss

Hey, 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 you 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, 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?view

Level4 Unit2 Part2 Listening

Point of view

This man is holding a piece of fruit in his hand. The piece of fruit is either an orange or

an apple. We can’t see

which it is because we can’t 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. It’s got to be one or the other. It can’t be

anything else.

Now let’s look at it from the man’s 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%. That’s because he knows what he has. For

him there is no uncert

ainty. If he has an orange, the probability is 100%. If he doesn’t have an orange, the

probability is 0%.? He either has it or he doesn’t.

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 see things from different points of view. This often leads to arguments between people. Here are some

examples. From this man’s point of view, he is relaxing. He needs t

o relax because he has been working too

hard. He hasn’t been getting enough sleep.

His wife sees things differently. She isn’t 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 arou

nd the house. It isn’t 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

differences can cause real communication problems.

Level4 Unit2 Part2 Vocabulary

Disasters

Earthquakes 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 chemical 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 serious 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 charges in the atmosphere that produce lightning, which can cause forest fires. Some storms

cause flooding and major damage to homes and cities.

Religions

Followers of the Islam religion are called Muslims. These Muslims are praying inside a mosque. Muslims are

called to prayer 5 times a day, beginning just 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.