题目
题型：同步题难度：来源：
astrophysicist (天体物理学家) Stephen Hawking moved backward last week.
The world-famous writer of "Brief History of Time" said he and other scientists had got it wrong.
"I"ve been thinking about this problem for the last 30 years, and I think I now have the answer to it,"
said Hawking. "A black hole only appears to form but later opens up and set free information about
what fell inside. So we can be sure of the past and can predict the future."
The findings could help solve the "black hole information paradox(似是而非的观点)", an important
puzzle in modern physics.
A black hole is an area in space where matter is under such pressure that even light can not escape
from its gravitational pull(引力). But, exactly what happens there has long puzzled scientists.
Black holes occur when a powerful star burns up its nuclear fuel and gravity forces it to break down
in on itself. The great weight of the star"s outer layers moves in towards its center. The force of gravity
keeps nearly all light from escaping and nothing inside can be seen from the outside.
The star actually disappears from the universe into a point of infinite density(高密度). That is a place
where the laws of general relativity that govern space and time break down.
Hawking has devoted most of his life to studying these questions.
At the beginning, cosmologists believed the holes were like a "universal vacuum (真空) cleaner",
sucking up everything in their path.
Hawking revolutionized the study of black holes when he proved, in 1976 that, under the strange
rules of quantum physics(量子物理), when black holes form they send out energy and lose mass in the
process.
In thinking up this so-called "Hawking radiation", the Cambridge mathematician also created one of
the biggest puzzles in physics.
These particles (粒子), he said, contained no information about what has been occurring inside the
black hole, or how it formed. Under his theory, once the black hole disappears, all the information within
it is lost.
B. They has solved the mystery of "black holes".
C. We can now know what is going on inside "black holes".
D. Scientists have already predicted the future of "black holes" now.
B. A person who studies the stars and their development.
C. A person who travels in a spacecraft.
D. A person who studies the position of the stars and the movements of the planets.
B. During the course of the black hole"s forming the enormous weight of the star"s center
moves into the outer layers.
C. Almost nothing can escape from the gravitational pull of the black hole.
D. Scientists have been thinking the black hole contains no information.
B. Black Hole Information Paradox
C. Black Hole Mystery
D. The Cause of the Black Hole
答案
核心考点
试题【 After almost 30 years of arguing that a black hole swallows up everything 】；主要考察你对题材分类等知识点的理解。[详细]
举一反三
the needs of man. The sea has provided man with food and a convenient way to travel to many parts
of the world. Today, nearly two-thirds of the world"s population live within 80 kilometers of the sea
coast.
In the modern technological world, the sea offers many resources to help mankind survive.
Resources on land are beginning to be used up. The sea, however, still can be hoped to supply many
of man"s needs.
The list of riches of the sea yet to be developed by man"s technology is impressive. Oil and gas
explorations have been carried out for nearly 30 years. Valuable amounts of minerals exist on the
ocean floor ready to be mined.
Fish farming promises to be a good way to produce large quantities of food. The culture of fish
and shellfish is an ancient skill practiced in the past mainly by Oriental people.
Besides oil and gas, the sea may offer new sources of energy. Experts believe that the warm
temperature of the ocean can be used in a way similar to the steam in a steamship. Ocean currents
and waves offer possible use as a source of energy.
Technology is enabling man to explore ever more deeply under the sea. The development of
strong, new materials has made this possible.
The technology to harvest the sea continues to improve. Experts believe that by the year 2050
the problems that prevent us from exploiting fully the food, minerals, and energy sources of the sea
will be largely solved.
B. Sea Harvest and Food
C. Sea and Sources of Energy
D. Sea Exploring Technology.
B. technology for exploring the sea has been solved
C. harvesting rice in the sea will be made possible
D. in the near future man can live on the ocean floor
B. To show that a steamship is better than other kinds of ships.
C. To argue that man should use steamships.
D. To indicate that it is warmer in the ocean than on land.
B. man can use it to explore the deeper sea
C. it is a lot of fun diving into the sea
D. ancient people used it to explore the sea
B. At the end of the 20th century.
C. In the near future.
D. By the middle of the 21st century.
fiction. Hundreds of titles are published every year and are read by all kinds of people. Furthermore,
some of the most successful films in recent years have been based on science fiction stories.
It is often thought that science fiction is a fairly new development in literature, but it can be found in
books written hundreds of years ago. These books were often concerned with the presentation of some
form of ideal society, a theme which is still often found in modern stories.
Most of the classics of science fiction, however, have been written within the last one hundred years.
Books by writers such as Jules Verne and H. Wells, to mention just two well-known authors, have been
translated into many languages. Modern science fiction writers don"t write about men from Mars or space
adventure stories. They are more interested in predicting the results of technical developments on society
and the human mind or in imagining future world which results the world we live in now. Because of this
their writing has obvious political undertones.
In an age where science fact frequently overtakes science fiction, the writers may find it difficult to keep ahead of scientific advances.Those who see the future clearly can teach us how to master new technology
and live in a rapidly changing world.
B. only in books written for children
C. in books written today and hundreds of years ago
D. as a new development in literature
B. writing about everything but politics
C. imagining future world with the results of technical developments
D. writing space adventure stories
B. shows the writer"s viewpoints
C. is not as good as that in the past
D. is better than other literary forms
B. adopting new technology and adapting quickly to its effect on society
C. conflict caused by different religious beliefs
D. space adventure
B. Writers may find it hard to keep ahead of scientific advances.
C. Some of the most successful films of recent years have been based on science fiction stories.
D. Those writers who can see clearly the way we are going will give us valuable instructions.
Brain-computer interface (界面) (BCI) technology could help people with disabilities send
commands to machines.
Recently, two researchers, Jose Milan and Michele Tavella from the Federal Polytechnic school
in Lausanne, Switzerland, demonstrated(展示)a small robotic wheelchair directed by a person"s
thoughts.
In the laboratory, Tavella operated the wheelchair just by thinking about moving his left or right
hand. He could even talk as he watched the vehicle and guided it with his thoughts.
"Our brain has billions of nerve cells. These send signals through the spinal cord(脊髓)to the
muscles to give us the ability to move. But spinal cord injuries or other conditions can prevent these
weak electrical signals from reaching the muscles," Tavella says. "Our system allows disabled people
to communicate with external world and also to control devices."
The researchers designed a special cap for the user. This head cover picks up the signals from the
scalp(头皮) and sends them to a computer. The computer interprets the signals and commands the
motorized wheelchair. The wheelchair also has two cameras that identify objects in its path. They
help the computer react to commands from the brain.
Prof. Milan, the team leader, says scientists keep improving the computer software that interprets
brain signals and turns them into simple commands. "The practical possibilities that BCI technology
offers to disabled people can be grouped in two categories: communication, and controlling devices.
One example is this wheelchair."
He says his team has set two goals. One is testing with real patients, so as to prove that this is a
technology they can benefit from. And the other is to guarantee that they can use the technology over
long periods of time.
1. BCI is a technology that can _________________.
B. link the human brain with computers
C. help the disabled to recover
D. control a person"s thoughts
2. How did Tavella operate the wheelchair in the laboratory?
A. By controlling his muscles.
B. By talking to the machine.
C. By moving his hand.
D. By using his mind.
3. Which of the following shows the path of the signals described in Paragraph 5?
B. computer→cap→scalp→wheelchair
C. scalp→cap→computer→wheelchair
D. cap→computer→scalp→wheelchair
4. The team will test with real patients to .
B. prove the technology useful to them
C. make them live longer
D. learn about their physical condition
B. New Findings About How the Human Brain Works
C. BCI Could Mean More Freedom for the Disabled
D. Robotic Vehicles Could Help to Cure Brain Injuries
school in 2 I have ever taught has ever ignored spelling or considered it unimportant as a basic
skill. There are, however, different ideas about how to teach it, or how much priority(优先) it must
be given over general language development and writing ability. The problem is how to encourage a
child to express himself freely and confidently in writing 3 holding him back.
If spelling becomes the only focal(焦点的) point of his teacher"s interest, clearly 4 bright child
will be likely to "play safe". He will tend to write only words within his spelling range, 5 (choose)
to avoid adventurous language. That"s why teachers often encourage the early use of dictionaries and
pay attention to content rather than technical ability.
Once I 6 (shock) to read on the bottom of a sensitive piece of writing about a personal
experience. "This work is horrible! There are far too many spelling errors and your writing is terrible.
" 7 may have been a sharp criticism of the pupil"s technical abilities in writing, but it was also a sad
8 (reflect) on the teacher who had omitted(忽视) to read the essay, 9 there existed some
beautiful expressions of the child"s deep feelings. The teacher was not wrong to draw attention to
the errors, 10 if his priorities had centered on the child"s ideas, an expression of his disappointment
with the presentation would have given the pupil more motivation to seek improvement.
discovered that subterranean (地下的) and aboveground herbivorous (食草的) insects can
communicate with each other by using plants as telephones. Subterranean insects issue chemical
warning signals through the leaves of the plant. This way, aboveground insects are warned that the
plant is already "occupied".
Aboveground, leaf-eating insects prefer plants that have not yet been occupied by subterranean
root-eating insects. Subterranean insects send out chemical signals through the leaves of the plant,
which warn the aboveground insects about their presence. This messaging makes it possible for
spatially-separated insects to avoid each other, so that they do not compete for, the same plant.
In recent years it has been discovered that different types of aboveground insects develop slowly
if they feed on plants that also have subterranean insects and "vice versa (反之亦然). It seems that a
mechanism (机制) has developed through natural selection, which helps the subterranean and
aboveground insects to communicate with each other. This avoids unnecessary competition.
Through the "green telephone lines", subterranean insects can also communicate with a third party,
namely the natural enemy of caterpillars (毛虫). Parasitic wasps (寄生蜂) lay their eggs inside above
ground insects. The wasps also benefit from the signals sent by the leaves, as these help them find more
insects for their eggs.
The communication between subterranean and above- ground insects has only been studied in a
few systems. It is still not clear how widespread this phenomenon is, say the researchers.
B. By giving off particular smells.
C. By making soft and beautiful sounds.
D. By the signals sent by parasitic wasps.
B. choose to leave the plant
C. compete for the same plant
D. fight with the root-eating insects
B. are not occupied by mot-eating insects
C. have more green leaves
D. have more subterranean insects
A. Aboveground insects.
B. Root-eating insects.
C. Caterpillars.
D. Parasitic wasps.
B. How do animals avoid competition?
C. Insects use plants as telephones
D. When plants have subterranean residents
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