well as ever when he gets back in the water. He can get on a bicycle after many years and still ride away. He can play catch and hit a ball as well as his son. A mother who has not thought about the words for
years can teach her daughter the poem that begins "Twinkle, twinkle, little star" or remember the story of
Cinderella or Goldilocks and the Three Bears.
One explanation is the law of overlearning, which can be stated as follows: Once we have learned something, additional(额外的) learning trials(尝试)increase the length(长度) of time we will remember it.
In childhood we usually continue to practice such skills as swimming, bicycle riding, and playing
baseball long after we have learned them. We continue to listen to and remind ourselves of words such as "Twinkle, twinkle, little star" and childhood tales such as Cinderella and Goldilocks. We not only learn but overlearn.
The multiplication tables(乘法口诀表)are an exception(例外) to the general rule that we forget rather quickly the things that we learn in school, because they are another of the things we overlearn in
childhood.
The law of overlearning explains why cramming(突击学习)for an examination, though it may result in a passing grade, is not a satisfactory way to learn a college course. By cramming, a student may learn the
subject well enough to get by on the examination, but he is likely soon to forget almost everything he
learned. A little overlearning, on the other hand, is really necessary for one"s future development.
1. What is the main idea of paragraph I?
A. People remember well what they learned in childhood.
B. Children have a better memory than grown-ups.
C. Poem reading is a good way to learn words.
D. Stories for children arc easy to remember.
2. The author explains the law of overlearning by_________.
A. presenting research findings
B. setting down general rules
C. making a comparison
D. using examples
3. According to the author, being able to use multiplication tables is_______.
A. a result of overlearning
B. a special case of cramming
C. a skill to deal with math problems
D. a basic step towards advanced studies
4. What does the word "they" in Paragraph 4 refer to?
A. Commonly accepted rules.
B. The multiplication tables.
C. Things easily forgotten.
D. School subjects.
5. What is the author"s opinion on cramming?
A. It leads to failure in college exams.
B. It"s helpful only in a limited way.
C. It"s possible to result in poor memory.
D. It increases students" learning interest.
Sharks are among the oldest animals on Earth.There are hundreds of kinds of sharks.Most are about
two meters long.The dogfish shark, however, is less than twenty centimeters in length.A shark has an
extremely good sense of smell.It can find small amounts of substances in water, such as blood, body
liquids and chemicals produced by animals.__1__ Sharks eat fish, other sharks, and plants that live in the
ocean.
Sharks grow slowly.About forty percent of all sharks lay eggs.__2__Some sharks carry their young
inside their bodies as humans do.Some sharks are not able to reproduce until they are twenty years old.
Most reproduce only every two years.And they give birth to fewer than ten young sharks.For this reason, overfishing of sharks is of special danger to the future of the animal.
Sharks are important for the world"s oceans.They eat injured and diseased fish.Their hunting activities
mean that the numbers of other fish in ocean waters do not become too great.__3__
People hunt sharks for sport, food, medicine and their skin.Experts say the international market for some
kinds of sharks has increased because many parts of a shark are valuable.
Collectors pay thousands of dollars for the jaws of a shark.__4__The skin of a shark can be used like
leather.
In Asia, people enjoy a kind of soup made from shark fins.Experts say a fisherman can earn a lot of
money for even one kilogram of shark fins.Sharks are among the oldest animals on Earth, but some sharks are in danger of disappearing from Earth.__5__
A. Shark liver oil is a popular source of Vitamin A.
B. This protects the plants and other forms of life that exist in the oceans.
C. Sharks are valuable to us and we can make full use of them.
D. These powerful senses help sharks find their food.
E. If too many sharks in one area are killed, that group of sharks may never return to normal population
levels.
F. They are a threat to other forms of life in the ocean.
G. The others give birth to live young.
Like distance runners on a measured course, all of us will move through time in a roughly predictable
pattern.
In the first stage of our lives, we develop and grow, reaching toward the top of physical
vitality(energy).
After we grow up,however, the body begins a process of gradually wearing out.
A new awareness of physical fitness may help lengthen our years of health and vitality, yet nothing we
do will work to stop the unavoidable force of aging.
Most of the changes of aging take place deep inside the body. The lungs become less able to take in
oxygen. Powerful muscles gradually lose their strength. The heart loses power and pumps less blood.Bones grow easier to break.
Finally, we meet a stress,a stress that is greater than our physical resistance. Often it is only a minor
accident or chance infection(a disease eaused by virus), but this time,it brings life to an end.
In 1932, a classic experiment nearly doubled the lifetime of rats, simply by cutting back the
calories(unit for measuring the energy value of food)in their diet.The reason for the effect was then
unknown.
Today, at the university of California at Berkley, Dr.Paul Seagle has also greatly lengthened the
normal lifetime of rats. The result was achieved through a special protein(蛋白质)limited diet, which
had a great effect on the chemistry of the brain. Seagle showed that within the brain, specific chemicals
control many of the signals that influence aging. By changing that chemical balance, the clock of aging
can be reset.
For the first time, the mystery(something that is difficult to understand or to explain)of why our age
is being seriously challenged. Scientists in many fields are now making striking and farreaching
discoveries.
An average lifetime lasts 75 years, yet in each of us lies a potential for a longer life. If we could keep
the vitality and resistance to disease that we have at age twenty, we would live for 80 years.
1. What does the underlined word"it" refer to?
A. Physical vitality.
B. Stress.
C. Aging.
D. Physical resistance.
2. The author believes the following EXCEPT that ________.
A. human"s life pattern is predictable
B. physical fitness can"t stop the force of aging
C. human"s lifetime will last longer than 75 years
D. all of the changes of aging take place deep inside the body
3. How did Dr.Paul Seagle lengthen the lifetime of rats in his experiment?
A. By limiting the protein in their diet.
B. By cutting the calories in their diet.
C. By resetting their clock of aging.
D. By keeping their physical fitness.
4. What is probably the best title for the article?
A. Two Great Experiments
B. The Mystery of Human Life
C. Ways to Lengthen Human Life
D. The Breakthrough in the Study of Aging
Lake Ontario.Surprisingly,the 22gun ship is wellpreserved in the cold,deep water.Explorers
announced the news recently.
Kennard is an electrical engineer.He has been diving for nearly 40 years and has found more
than 200 wrecks(残骸) in the Great Lakes and other lakes or rivers.He began searching the
Ontario 35 years ago but quit after several dives.Six years ago,he began to work with Scoville,a
diver.Since then,the pair have found seven ships in the lake.Over the years,Kennard got licenses
and information,including the ship"s design plans,from the British government.Even then,it took the
pair three years to search more than 200 square miles before they found the ship earlier this month.
After locating the wreck with the sonal(声纳),the explorers used a submarine to confirm their
find.The 80foot ship is the only entire British ship ever found in the Great Lakes,Scoville and
Kennard said."To have a ship from the Revolutionary War that"s nearly entire is unbelievable.It"s
an archaeological miracle."They said the ship is still considered the property of the British Admiralty.
Although the ship sits in an area where the water is up to 500 feet deep and cannot be reached by
anyone but the most experienced divers,Kennard and Scoville refused to give its exact location with
care.They only said that it was found off the southern shore.
The ship was discovered resting partially on its side.It went down on October 31,1780,with 60
British soldiers, a crew of about 40,mostly Canadians,and possibly about 30 American war prisoners.
The explorers also found two cannons and the ship"s bell.
B.has kept searching the Ontario for 35 years
C.is both an engineer and an experienced diver
D.got to know Scoville when he was very young
B.needed a lot of experts"s support
C.was forbidden by the government
D.was made completely by accident
B.will become world famous because of their find
C.may not have succeeded without modern technology
D.will be given a large reward by the American government
B.they were afraid that something unexpected might happen
C.they wanted to keep it a secret forever
D.they thought it would be interesting for people to guess where it is
nations.They say people should eat more of the same kind of food eaten by humans living more than
10,000 years ago.__1__
The scientists say that the human life has changed greatly.Our bodies have not been able to deal
with these changes in lifestyle and this had led to new kinds of sicknesses.__2__ So they are called
"diseases of civilization".Many cancers and diseases of the blood system are examples of such
diseases.
Scientists noted that people in both the Old Stone Age and the New Stone Age enjoyed very little
alcohol or tobacco,probably none.__3__ However,a change in food is one of the main differences
between life in ancient times and that of today.
Stone Age people hunted wild animals for their meat,which had much less fat than domestic ones.
They ate a lot of fresh wild vegetables and fruits.They did not have milk or any other dairy products,
and they made very little use of grains.__4__ We eat six times more salt than our ancestors.We eat
more sugar.We eat twice as much fat but only one third as much protein and much less vitamin C.
__5__ But scientists say that we would be much healthier if we eat much the same way as our ancestors
did,cutting the amount of fatty,salty and sweet food.
A.These new sicknesses were not known in ancient times.
B.People today probably do not want to live the way people thousands of years ago did.
C.Ancient people also lived in large groups.
D.But today,we eat a lot of these food.
E.Ancient people also got a great deal of physical exercise.
F.In that case,they would live much healthier.
G.People today probably live the same life as people thousands of years ago.
阅读理解。
Move Earth-it"s no science fiction
LONDON-Scientists have found an unusual way to prevent our planet from overheating:move it to
a cooler spot. All you have to do is send a few comets(彗星)in the direction of Earth, and its orbit will
be changed. Our world will then be sent spinning into a safer,c older part of the solar system.
This idea for improving our climate comes from a group of US National Aeronautics and Space
Administration (NASA) engineers and American astronomers. They say their plan could add another
six billion years to the useful lifetime of our planet-effectively doubling its working life.
The plan put forward by Dr. Laughlin, and his colleagues Don Korycansky and Fred Adams, needs
carefully directing a comet or asteroid so that it passes close by our planet and sends some of its
gravitational energy to Earth.
"Earth"s orbital speed would increase as a result and we would move to a higher orbit away from
the Sun,"Laughlin said.
Engineers would then direct their comet so that it passed close to Jupiter or Saturn. The comet
would pick up energy from one of these giant planets. Later its orbit would bring it back to Earth, and
the process would be repeated.
In the short term, the plan provides an ideal way to global warming,although the team was actually
concerned with a much greater danger. The sun is certain to heat up in about a billion years and so
"seriously compromise" our biosphere(生物圈)-by cooking us.
That" s why the group decided to try to save Earth.
The plan has one or two worrying aspects, however. For a start,space engineers would have to
be very careful about how they directed their asteroid or comet towards Earth. The smallest
miscalculation(误算)in orbit could fire it straight at Earth-with deadly consequences.
There is also the question of the Moon. As the current issue of Scientific American magazine
points out, if Earth was pushed out of its current position it is "most likely the Moon would be
stripped away from Earth," it states. This would greatly change our planet" s climate.
1. What makes the scientists plan to move Earth?
A. A few comets are moving to the direction of Earth.
B. Earth" s working life is coming to an end soon.
C. Earth will become too hot for mankind to keep alive.
D. The moon is moving farther and farther away from Earth.
2. If the plan is successful,Earth will have a working life of________years.
A. 12 billion
B. 6 billion
C. 18 billion
D. 24 billion
3. What serious problems might the plan cause according to the passage?
A. The comet might hit Earth and man might lose the moon.
B. Earth might be moved too far away and man might be frozen to death.
C. The comet might hit Jupiter or Saturn and never return to Earth.
D. Earth" s working life might be greatly shortened.
4. What does the underlined word "compromise" mean?
A. provide
B. benefit
C. share
D. endanger
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