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The zebra belongs to the horse family.One of nature"s great mysteries is why the zebra has stripes.One
theory is that the stripes help the zebra cool down.On hot days the black stripes get a lot hotter than the
white area of the zebra and under the black stripes there are special layers of fat for protection.Hot air then rises off the black stripes,forcing colder air down around the white areas,cooling the zebra down.This,
however,is just a theory.The stripes can also confuse predators (食肉动物) when zebras stay with other
animals in great numbers.
Zebras have excellent hearing and eyesight and can run at a speed of up to 35 miles per hour (56
kilometers per hour).They also have a powerful kick that can cause serious injury to a predator,like a
lion,or an African wild dog.Usually the lead male of the herd stays at the back of the group to defend
against predators if necessary,while the females and youngsters run from danger.
Zebras are herbivores and feed mostly on grasses,although they also might eat the leaves and stems (茎) of bushes a bit.They eat grasses for many hou
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time chewing wears the zebra"s teeth down,so their teeth keep growing all their lives.As the dry season
arrives and the grasses die back,zebra herds travel to find more food and water holes for drinking.Most
zebras have no specific territories.They travel from place to place,never staying in one area very long.
B. The black stripes help the zebra live through cold days.
C. The zebra can easily be attacked by predators.
D. The zebra always travels with other animals.
B. animals that only eat plants
C. animals that kill and eat other animals
D. animals that live in groups
B. are used all day
C. are always growing
D. are kept clean
B. Their stripes can confuse predators.
C. They can run 56 miles per hour.
D. They usually stay in one area all their lives.
B. Everyday Tips
C. Digital Stadium
D. Discoveries
infection.A study done by University of Michigan,has shown information that seems to be true for the
general population.Babies are the most cold infected group,generally more than six colds in their first year.Boys have more colds than girls up to the age of three.After three,girls are easier to get infected with cold
than boys,and teenage girls get three colds a year to boys" two.The general cold infections continue to get
less into adults.Elderly people who are in good health have as few as one or two colds every year.One
interesting thing is found among people in their twenties,especially women,who show a rise in cold
infection,because people in this age group are most likely to have young children.
The study has also found that economy plays an important role as well.With more and more income,
the frequency at which colds are reported in the family is getting lower and lower.Families with the lowest
income usually suffer about a third ally forces people to live in rooms more crowded than rooms owned by richer people,and the crowding usually leads to more chances for the cold virus to travel from person to
person.Low income may also have an effect on our diet.Many scientists believe that a poorer diet usually
leads into more possibilities of cold infection.
1.Which of the age groups has the highest frequency of cold infection?
A.Small babies.
B.Teenage boys.
C.Adult women.
D.Elderly people.
2.The purpose of writing this passage is to________.
A.give the readers some tips to avoid cold infection
B.show a carefullmade study on cold infection
C.report the major reasons leading to cold infection
D.describe all the possible dangers of cold infection
3.How does economy play an important role in cold infection?
A.Families with lower income suffer l
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B.People who have lower income enjoy living in crowded rooms.
C.Rich families can have better nutrition and never get infected.
D.People with higher income have fewer chances of infection.
4.From the passage we can infer that________.
A.age is the only important factor that connects with colds
B.families with the highest income will more easily get infected
C.people have lower frequency of infection as they grow older
D.a better diet may help people to fight against cold infection
1. Which of the following things will happen before an earthquake?
A. The water in the wells rises and falls.
B. The chickens are too nervous to eat.
C. Mice run out of the fields looking for places to hide.
D. All of the above.
2. What was the result of the earthquake?
A. Luckily,the city"s hospitals survived.
B. All of the city"s factories were gone.
C. Most of the city"s homes were gone.
D. The wind could blow the bricks on the ground away.
3. Who played the most important part in helping the people in the earthquake?
A. The soldiers and the rescue workers.
B. The college students.
C. The miners in the coal mines.
D. The injured and the dead.
4. What is the main idea of this passage?
A. The earth did not sleep that night.
B. An earthquake happened in Tangshan.
C. The animals could not sleep at night.
D. Earthquakes happen now and then.
The time and place | It happened on 1._______ 28, 1976 in Tangshan, 2. _________Province. |
Something before the earthquake | The water in the 3._________ rose and fell over and over. The well walls had deep 4._______in them and a smelly 5. ________came out of them. Some 6.________became abnormal The sound of planes could be heard and the water pipes cracked and 7. ___________ . |
The damages of the earthquake | The number of people killed or injured in the earthquake reached over 8. _________. Many people died or were 9._________ and many children became orphans. Nearly everything was 10._______ |
阅读理解 | |
Children start out as natural scientists, eager to look into the world around them. Helping them enjoy | |
阅读理解 | |
Are you ready to experience life as it may be in the future?Here are some interesting points to learn about the future. Artificial intelligence:Many years down the road humans might not even be recognizable because artificial intelligence (also known as AI) will have combined with our natural states.Scientists are learning more about the human brain every day, and they are working toward making smart robots we can use to help us.Some people say that nanobots-supertiny robots-may help us in invisible (看不见的) ways in the future.They say they will be everywhere, outnumbering humans many times over! Nanotechnology:This is the ability to make tools and helpful robots that are a billion times smaller than we can see.Scientists have already made many nanosized tools that they can use.When this science is improved and becomes more common and affordable, it will change everything. Braintocomputer communication:Nanocomputers will probably be linked to your thoughts, voice and emotions, and be able to react to your needs.In the future people will rely on wireless technology and everyone and everything will be linked.Your brain will be able to receive information from computers to fill your head with knowledge or teach you new things.When you want to learn a new skateboarding trick or dance move, nanocomputers will send the information to your brain and allow your body to use the tips and apply them-no studying involved! Virtual reality:You already love virtualreality games-they make imaginary worlds in which you can play. But what if it allows you to have a cool new school?Virtual worlds are being created so computergenerated environments will allow you to learn school lessons with your teacher and your friends seemingly present without actually being there.Technology will give you a 3D image and link it to your brain in a way that makes you actually feel as if you were there. 1. The passage mainly introduces________. A. the use of robots in the future B. the importance of science and technology C. some technology in the future D. some ways to improve communication 2. What can we conclude from the second paragraph? A. The number of robots is greater than the number of humans. B. AI will bring about great changes to people"s lives. C. Nanobots will take the place of humans in some years. D. Scientists won"t stop learning about the human brain until AI is widely used. 3. The fourth paragraph introduces a new way of________. A. delivering and getting information B. school education C. exercising D. entertaining 4. We can most probably read this passage in________. A. a government report B. a scientific magazine C. a news report D. a research paper |