【推荐3】One CT image of a brain changed science and medicine forever.

Half a century ago, the first CT image of a patient lifted the veil (面纱) of invisibility that covers the interior of the human body, providing scientists a window on our innards (内脏) unlike any before.

Today, doctors in the United States alone order more than 80 million scans per year. X-ray computed tomography, or CT, is frequently the quickest way of getting a handle on what’s causing a mysterious problem. CT scans can find out heart disease, tumors, blood clots, internal bleeding and more. The technique can give surgeons a heads-up about what they will encounter inside a patient, and guide treatment for cancer and other diseases.

“It answers so many questions quickly. That’s why it’s used,” says medical physicist Cynthia McCollough of the Mayo Clinic in Rochester, Minn.

A CT scan involves thousands of X-ray measurements taken from multiple angles. Here's how it works: A source of X-rays moves around the body, sending a beam (光束) of radiation through bone, blood and tissue, while moving detectors measure the beam that makes it through.

Different materials in the body absorb X-rays differently. The calcium (钙) in bone actively absorbs X-rays, for example, while soft tissues absorb less. So when the data collected by the detectors are joined together by a computer, it can form a cross-sectional view of what’s inside based on where X-rays are absorbed more or less. Moving the table holding the patient so that the X-ray beam and detectors slide along the body enables 3-D reconstructions of organs and other parts.

Over the years, scientists have continually improved the technology, making it faster and higher resolution (清晰度), and cutting the amount of radiation that patients receive. These improved CT scans have painted ever more detailed landscapes of the human body. It’s hard not to be impressed by the beauty of the inner world that the scans bring to the surface.

1. What does the underlined word “heads-up” in paragraph 3 mean?

A．Measure.

B．Choice.

C．Forecast.

D．Treatment.

2. How does CT help surgeons to detect problems?

A．By using different materials to absorb X-rays.

B．By collecting and sending data to the computer.

C．By checking the amount of calcium in the bone.

D．By scanning what’s inside based on different X-rays absorption.

3. Which of the following can reflect the improvement in X-rays technology?

A．Lower speed.

B．More radiation.

C．Higher resolution.

D．Fewer details.

4. What is the writer’s attitude towards CT scans?

A．Doubtful.

B．Positive.

C．Disapproving.

D．Indifferent.

【推荐1】Commuter trains are often crowded, and they frequently fail to run on time. As if that were not bad enough, physicist Hondou published a paper in 2002 that gave commuters yet another reason to feel uncomfortable.

Dr. Hondou examined mobile phone usage in enclosed spaces such as railway carriages, buses and lifts all of which are metal boxes. His model predicted that a large number of passengers crowded together, all talking, sending text messages, or browsing the web on their phones, could produce levels of electromagnetic radiation that exceed international safety standards. That is because the radio waves produced by each phone are reflected off the metal walls of the carriage, bus or lift. Enough radiation escapes to allow the phone to communicate with the network, but the rest fills the inside of the carriage with bouncing microwaves.

This sounds worrying. However, in a paper published recently, Jaime Ferrer and Lucas Fernandez-Seivane from the University of Oviedo in Spain, question the truth of Dr. Hondon's findings. They conclude that the level of radiation is safe after all.

In their opinion, while each phone produces radiation that bounces around the car, the passengers absorb some of it, which has the effect of reducing the overall intensity. Dr Hondou's model, in short, was logical only in the case of a single passenger sitting in an empty carriage with an active mobile phone on every seat.

According to Dr. Ferrer and his colleagues, Dr. Hondon overestimated the level of electromagnetic radiation. When one is sitting on a train, they found, the most important sources of radiation are one's own phone, and those of one's immediate neighbours. The radiation from these sources far exceeds that from other phones or from waves bouncing around the carriage. And all these sources together produce a level of radiation within the limits defined by the ICNIRP, the international body that regulates such matters.

People concerned about the effects of mobile-phone radiation are unlikely to take much comfort from Dr. Ferrer's results. Indeed, Dr. Ferrer says he is surprised at how little research has been done in this area.

Yet both Dr. Hondon's results and Dr. Ferrer's are based on mathematical models. Their models make assumptions about the physical properties of train carriages and their passengers, and both assume that the radiation is regularly distributed rather than gathered into “hot spots”. But if the debate about the safety of mobile phone is to be resolved, there must be less focus on models, and more emphasis on physical experimental data.

1. The paper published by Dr. Hondon make the commuters worried because _________.

A．he argues that commuter trains do not meet international radiation safety standards

B．he thinks that the radiation from mobile phones bouncing around in enclosed spaces is harmful

C．commuters fear that the metal walls of the railway carriage will threaten their health

D．commuters are afraid that a ban on the use of mobile phones on trains is approaching

2. What is the commuters' reaction after learning about the new research by Dr. Ferrer and his colleagues?

A．They don't worry about the safety of mobile phone any more.

B．They expect Dr. Ferrer to carry out more researches in this area.

C．They still have concerns over the mobile-phone radiation.

D．They find the results of all the researches boring.

3. Dr. Hondon's research and that of Dr. Ferrer share the following similarities EXCEPT _________.

A．their findings are developed from mathematical model

B．they focus on a single passenger in the empty railway carriage

C．the models assume certain physical properties of train carriages and the passengers

D．their models are built in a way that the radiation in the enclosed spaces is regularly distributed

4. What is the author's attitude toward the research on the effects of mobile-phone radiation?

A．He is surprised that too little research has been carried out in this area.

B．He thinks that the most important thing for the researcher is to perfect their models.

C．He is quite satisfied with the progress made so far.

D．He thinks researchers have to depend more on physical experiments.

【推荐2】Chemical farming is the most widespread way of farming. It is the conventional way in which large agricultural societies grow crops.     1     Organic farming, however, even though it may mean a greater cost of production and more work, has significant benefits on our health and the health of our planet.

Chemical farming has a negative impact on the environment. Pesticides are used to protect plants from various pests, diseases, and weeds.     2     Besides killing insects and weeds, pesticides can be poisonous to a great number of other organisms such as birds, fish, beneficial insects, and non-target plants. Another important issue is that the poisonous substances become airborne. They can drift away on distances up to a few miles, poisoning the air of nearby communities.

    3     Studies have shown that pesticide remains can be found in a variety of products, such as water, wine, vegetables, fruit juices, or grains. When we eat or drink these products, our health is likely to be harmed.

Organic farming relies on natural processes, biodiversity, and man-made fertilizer rather than the use of chemicals. In opposition to the negative effects that conventional farming has on the environment and human health, organic farming is an agricultural production system that does good to the health of soils, ecosystems, and people.     4     Organically grown food is higher in nutrients and free of poisonous remains.

For the benefit of our health and our planet, we have to change our ways of farming.     5    However, it is a better choice to build a better, healthier future for both our human communities and our environment.

A．Chemical farming does damage to our health in many ways.

B．The shift from chemical farming to organic farming may take time.

C．Organic farming has great potentials in agricultural in future farming.

D．However, pesticides can also pollute the soil, water, or other vegetation.

E．It has been practiced in many agricultural countries for many many years.

F．It may be the cheapest and easiest option but it surely isn’t the best choice.

G．It produces no environmental pollution and offers various benefits to health.

【推荐3】One of the earliest forms of writing which is still being used today is Chinese characters, or hanzi. The image that many people have of Chinese characters is that they are all pictograms, but this is far from the case because pictograms have very limited use. Simple pictograms might be practical, for example, if one is making a shopping list of items to buy at the store, but they are fairly useless if one is writing something more complex or abstract. So it is a mistake to assume that written Chinese is a “picture language”．

Besides pictograms, there are simple ideograms. These are characters which provide an abstract picture of an idea, but in an often easily recognizable form. For example, “up” is “上” while “down” is “下”. While the meanings of many ideograms are not this easy to work out, they tend to be simple, easy-to-remember characters which are commonly used.

Next we have a common category of hanzi: compound characters. These are where elements of two or more characters are combined in one character for a new meaning. Some of these are easy to understand. In many cases, however, the meanings of compound characters are more difficult to work out.

Phonetic loan characters are the characters which started out as pictograms. However, they were often used to mean other words that had the same pronunciation. A good example of this is “目”. While it can be used in modern Chinese with the meaning “eye”, it is most often used to mean “an item on a list”. The reason was that Chinese had a word for “an item on a list” but lacked a character for it, so the word took the character “目”, a character with the same pronunciation.

A final category of Chinese characters is by far the most common. These are phonetic-semantic characters. With phonetic-semantic characters, one element of each character gives a clue to the pronunciation, while the other gives a clue to the meaning.

Over the centuries, Chinese characters have continually been developed, with a trend towards the simple and more abstract. It was thought that the complexity of some Chinese characters was keeping people from being able to learn them. Thus, during the 1950s and 1960s, the Chinese government rolled out simplified Chinese characters.

1. Why are pictograms sometimes not practical for use in a writing system?

A．They are only available for shopping.

B．They are too complex for people to learn.

C．They cannot convey abstract ideas very well.

D．They are quite complicated and difficult to write.

2. What do we know about compound characters according to the passage?

A．They are drawings of objects used in a writing system.

B．They are characters which use elements of two or more characters.

C．They are characters used in a writing system to convey abstract concepts.

D．They are characters which give clues to both the meaning and pronunciation.

3. Which of the following categories does the character “模” belong to?

A．Pictograms.	B．Phonetic loan characters.
C．Ideograms.	D．Phonetic-semantic characters.

4. What would be the benefit of simplifying Chinese characters according to the passage?

A．Creating a standard character set for China.

B．Visualizing the image of Chinese characters.

C．Popularizing the use of Chinese characters.

D．Reproducing a high-grade character for calligraphy.

【推荐2】With the world’s attention on vaccines (疫苗), now feels like a good moment to sing the praises of an often forgotten contribution to their development. Three hundred years ago this month, Lady Mary Wortley Montagu got her daughter inoculated (接种) against smallpox, making her child the first person in the West to be protected in this way. Without Montagu’s willingness to adopt a practice she had learned from other cultures, the introduction of vaccines around 80 years later would never have taken place.

Montagu first witnessed inoculation when she accompanied her husband to Turkey in 1717. Inoculation had started in Asia, probably in China, as early as the 10th century AD. Montagu observed how older women in Turkey took a tiny amount of pus (脓) from a person with smallpox. They then used needles to make cuts on people’s wrists and ankles and added the pus to their bloodstream. This helped people gain immunity from future infection.

Like other visitors to the country, Montagu took steps to ensure that her son was inoculated in Turkey. This worked well, but she knew that trying it in England would be far more challenging. Inoculation performed by unlicensed amateurs would threaten doctors’ professional standing and potentially rob them of valuable income. Churchmen also disagree with the practice, as they saw it as going against nature.

Back in England, Montagu observed the increased severity of smallpox infections. Eventually, in April 1721, she decided to use the Turkish practice to have her daughter inoculated, because she believed that the rewards would outweigh the risks. After a safe time had passed following the inoculation, Montagu allowed doctors to examine her daughter.

Doctors in Britain gradually accepted the practice. About so years later, a pioneering physician found smallpox vaccines to destroy smallpox completely. As early as last century, academics argued that Montagu was no more than an enthusiastic amateur. In truth, she made a vital scientific contribution towards finding the cure for smallpox.

1. What is the second paragraph mainly about?

A．The origin of smallpox inoculation.

B．Montagu’s first access to inoculation.

C．The benefits from smallpox inoculation.

D．Turkish women’s invention of inoculation.

2. Montagu found it difficult to try inoculation in England because ________.

A．it was against human nature	B．it might harm doctors’ interests
C．it was beyond doctors’ abilities	D．it might shake churchmen’s belief

3. What led doctors in Britain to accept inoculation?

A．The increased severity of smallpox infections.

B．A physician’s discovery of smallpox vaccines.

C．The result of Montagu’s daughter’s inoculation.

D．Montagu’s focus on its rewards rather than its risks.

4. What might be the best title of the test?

A．An unsung hero	B．No limit to creation
C．Development of vaccines	D．A historic medical innovation