Many of us have wondered what Earth is like beneath the surface. So have writers and scientists. In French novelist Jules Verne's masterpiece Journey to the Center of the Earth, explorers go down to Earth's center and discover amazing wonders.
But in real life, human beings haven't even come close to the planet’s core (核心). The core is over 6,000 km down. The deepest hole ever created, according to the BBC, is the Kola Superdeep Borehole in Russia, which only goes 12.3 km down.
So how do we know about everything down. below without any samples? One good way to start is to think about the Earth's density, Simon Redfern of the University of Cambridge in the UK told the BBC. ''The density of the material on Earth's surface is much lower than the average density of the whole Earth, so that tells us there's something that has greater density, '' Redfern said.
The challenge is to find out which heavy materials the core is made of. And the main material scientists have found is iron. The idea is that when Earth formed 4.5 billion years ago, a lot of iron made its way down to the core, taking up about 80 percent of it. Today scientists are still working on finding out which other materials the core could be made up of.
You might also wonder how we know the size of the core. There's a one-word answer: seismology (地震学). When an earthquake happens, seismic stations around the world record the shockwaves it. sends throughout the planet. It's like hitting one side of the planet with a huge hammer and listening on the other side for the noise.
Early research found that some shockwaves, called S-waves, went missing. S-waves can only travel through solid material, but not through liquid, so they must have found something molten in Earth's center. By following the S-waves paths, scientists found out that rocks became liquid around 3,000 km down.
There are still many questions about Earth's core to answer. But the study of the dark world below isn't just for scientists' curiosity. The movement of Earth’s molten iron core builds up a powerful magnetic field. It protects us from radiation from the sun and is needed for compasses and GPS systems to work.
So perhaps none of us will ever set eyes on the core, but it's good to know it's there.
1. The author mentions Jules Verne's novel Journey to the Center of the Earth in the first paragraph to ________.| A．discuss the possibility of going down to Earth's center |
| B．show how much humans have discovered about Earth |
| C．paint a picture in our imagination of the dark world below |
| D．show humans deep interest in Earth's center |
| A．Earth’s center is completely made up of iron. |
| B．Scientists have found samples of Earth's core from the Kola Superdeep Borehole. |
| C．Scientists have no idea when and how iron made its way down to Earth’s core. |
| D．Earth has a higher density at its core than on its surface. |
| A．are often used to predict' earthquakes | B．cannot travel through liquid material |
| C．are the most noticeable shockwaves produced by earthquakes | D．can travel most rapidly at 3 ,000 kilometers below Earth's surface |
| A．research into Earth's core has hardly made any progress in recent years |
| B．improvements in GPS systems could help people find out more about Earth |
| C．Earth's core helps to protect humans from harm |
| D．scientists are likely to reach Earth's center within dozens of years |
相似题推荐
【推荐1】Microplastics, the kind of current working definition, is plastic less than five millimeters. So people commonly equate that to something like a grain of rice or a sesame (芝麻籽) seed and down in terms of size class. I will say that most of the microplastics that people are interacting with are quite a bit smaller than the sesame seed size, which I think always kind of shocks people when we start talking about the numbers because they kind of can’t see a lot of these things, at least with the naked eyes.
Kieran Cox is a PhD candidate in marine biology at the University of Victoria and one of the authors of the study, which is in the journal Environmental Science & Technology. For their study, Cox and his team pulled together past scientific literature that calculated the number of microplastics in things we commonly consume, such as in tap and bottled water, sugars, seafood—even in the air that we breathe. This analysis helped them figure out the baseline amount of microplastics that people are consuming every year. They couldn’t include common foods like beef, vegetables and dairy in their analysis because data on them doesn’t exist yet. In fact, their study could account for only 15 percent of people’s caloric intake. Even missing the majority of what people swallow, the research revealed that—at the very least—humans appear to consume somewhere between 74 000 and 121 000 microplastic particles every year. That number goes up for people drinking bottled water rather than tap water.
Now, is all the plastic safe to take in? Scientists simply don’t know yet. “This is kind of the first estimate of dose (剂量), you could say, right? So if you’re thinking in terms of toxicology (毒理学) and ecotoxicology, dose is a very important factor to think about, and so this kind of presents the first estimate, but it is very much an underestimate because of what we don’t know.”
1. What is microplastics?| A．Particles like a grain of rice. |
| B．Plastic particles smaller than 5 mm. |
| C．Something smaller than a sesame seed. |
| D．Something to be seen with naked eyes. |
| A．The study of the amount of microplastics people consuming. |
| B．Calculation of the amount of microplastics in food. |
| C．Analysis of past scientific literature. |
| D．The study of marine biology. |
| A．Making plastics safe. |
| B．The number of bottled water. |
| C．Safe dose of microplastics. |
| D．The things people swallow. |
| A．It has been published in the journal. |
| B．Kieran Cox is the director of the study. |
| C．The first estimate is accurate. |
| D．It is related to life security. |
Cyber security firm Hold Security discovered the security breach(漏洞 ). The firm found that the group of criminals collected personal information from 420,000 websites, including household names and small Internet sites. The criminals were based in a small city in south central Russia. They hacked websites inside Russia as well as big companies in the U.S. and other countries ,The New Times reports.
The criminals found hundreds of thousands of weak websites and attacked their coding，Hold Security said. Alex Holden is chief information security officer of Hold Security. “The hackers did not just target U.S. companies；they targeted any website they could get，” Holden said. “And most of these sites are still easy to attack”.
According to Hold Security, the criminals have been using the stolen information to send junk mail through e-mail and on social networks like Twitter. They can also use the 500 million stolen e-mail -addresses to plan other crimes. They could use information from bank e-mails to steal your identity or sell the e-mail address to other criminals to make quick cash.
The reported break-ins are the latest events to raise doubts about security at big and small companies. Last winter, hackers stole 40 million credit card numbers and 70 million addresses, phone numbers and other personal information from the retailer Target Corp. The brand is still working to regain its shoppers' trust.
John Prisco is a CEO of a security firm. He says security hacks are more common than many people and companies realize. "
Security experts believe hackers will continue breaking into computer networks unless companies become more protective of personal information.
1. What did a group of Russian criminals do according to the report?
| A．They stole e-mail addresses of the Internet users. |
| B．They destroyed the websites of some big companies. |
| C．They attacked American companies in southern Russia. |
| D．They downloaded the secret information of some banks. |
| A．some websites don't have their own coding |
| B．most of the websites lack protective measures |
| C．Russia is more developed in computer science |
| D．the hackers are equipped with high technology |
| A．The criminals are fond of using social networks. |
| B．The criminals sell the stolen information for money. |
| C．The stolen information causes great economic losses. |
| D．The stolen information could bring harmful effects. |
| A．We cannot tell how large an iceberg is just from the part on the water. |
| B．Many companies are unwilling to report their information stolen. |
| C．Many companies are not aware their information has been stolen. |
| D．People usually can see just a small part of an iceberg. |
In 2002, Gerianne M. Alexander of Texas A&M University and Melissa Hines of City University in London surprised the scientific world by showing that monkeys showed the same sex typical toy preferences as humans. In the study, Alexander and Hines gave two masculine toys (a ball and a police car), two feminine toys (a soft doll and a cooking pot), and two neutral(中性的) toys (a picture book and a stuffed dog) to 44 male and 44 female monkeys. They then assessed the monkeys’ preference for each toy by measuring how much time they spent with each. Their data showed that male monkeys showed significantly（显著地） greater interest in the masculine toys, and the female monkeys showed significantly greater interest in the feminine toys. The two sexes did not differ in their preference for the neutral toys.
If children’s toy preferences were largely formed by gender socialization, as traditional sociologists’ claim, in which their parents give “gender appropriate” toys to boys and girls, how can these male and female monkeys have the same preferences as boys and girls？They were never socialized by humans, and they had never seen these toys before in their lives.
1. Traditional sociologists believe boys’ and girls’ toy preferences ________.
| A．are passed down from their parents |
| B．have a biological origin |
| C．have nothing to do with gender socialization |
| D．are largely formed in later life |
| A．also play toys as humans do |
| B．also have a sex typical toy preference |
| C．have no toy preferences |
| D．like to play different toys at different time |
| A．find out why boys and girls prefer different toys |
| B．test the intelligence of monkeys |
| C．test whether monkeys like to play toys |
| D．find more evidence for traditional sociology |
| A．monkeys | B．adult | C．boys | D．girls |
【推荐1】As the world sees more and more extreme weather patterns, it's becoming increasingly difficult to ignore the effects of climate change. It is now a common topic of discussion and it has even found its way into the books we read. Because of this, a genre（类型）called climate fiction, or cli-fi, has found new life.
The term “cli-fi” was first used in 2007 by US climate activist and writer Dan Bloom. According to Bloom, the term really gained popularity when Canadian writer Margaret Atwood used it in a tweet, introducing it to her half-a-million followers.
As the name suggests, climate fiction refers to stories with a central theme of climate change or global warming. These kinds of books can help us imagine what the world might be like in the future because of major climate change events.
Adeline Johns-Putra is a professor of literature in Suzhou and has edited many books on climate fiction. “It's a part of a pattern,” Johns-Putra told Smithsonian Magazine. “It's a feedback loop（环）, as these books feed into our awareness and that feeds into our demand to read these books.”
The genre is also gaining popularity with high school and college students because it is relevant to what's really happening today. Also, many cli-fi novels tend to have dystopian（反乌托邦的）themes, which are very popular in young adult novels.
In 2015, cli-fi author Sarah Holding wrote for The Guardian that cli-fi “reconnects young readers with their environment”, which helps them appreciate it more, “especially when today, a large amount of their time is spent in the virtual world”.
Cli-fi has also helped to inspire students to pursue science majors. “These books aren’t going to save the world in any straight form or way,” Johns-Putra commented. “But they're certainly going to help us think about how the world gets saved.”
As Atwood wrote in her dystopian cli-fi novel MaddAddam, “People need such stories, because however dark, a darkness with voices in it is better than a silent void（空间）.”
1. What does cli-fi refer to?| A．Stories about country life. | B．Stories about climate change. |
| C．Stories about the future. | D．Stories about dystopian themes. |
| A．It raises their awareness of the real world. |
| B．It teaches them to appreciate what they have. |
| C．It makes them more interested in the virtual world. |
| D．It encourages them to write their own cli-fi novels. |
| A．It is too dark for people. |
| B．It tends to make people feel empty. |
| C．It should involve different voices. |
| D．It can get people thinking about their reality. |
| A．To introduce a genre of fiction. |
| B．To war readers of future climate crises. |
| C．To praise a famous US climate activist. |
| D．To inspire students to pursue science majors. |
【推荐2】In today’s world of mobile payment, all we really need is a smartphone. But the traditional wallet(钱包) became popular again after Azat Tovmasyan, who used to lose his wallets, had a creative idea. Thus, Volterman smart wallet was born, aiming to make traditional wallets cool again by bringing them into the high-tech age.
Volterman smart wallet takes wallet safety to a new level. It’s equipped with high-tech functions, such as an alarm, which will warn you so that you don’t leave it behind. And if your wallet is lost or stolen, the GPS tracker can help you find it.
Even more interesting is the front-facing camera. “If someone dares to open your wallet secretly, a little camera inside will take a picture and send it to your mobile phone through the Internet,” Azat Tovmasyan said. “Once your wallet is stolen, you will find it easily with the help of a picture of the thief,” he added.
The high-tech wallet will be released(发行) later this year and will come in three models, with the cheapest one costing $179.
1. Which is TRUE, about the smart wallet according to the text?| A．It can be found at shops now. |
| B．It is cheaper than the traditional wallet. |
| C．It can’t be opened by anyone else except the owner. |
| D．It can be connected with the smartphone through the Internet. |
| A．The technology. | B．The price. | C．The logo. | D．The inventor. |
| A．A travel journal. | B．A science magazine. | C．A research paper. | D．An art website. |
【推荐3】Ah, earth’s oceans. They are beautiful, inspiring and life-sustaining. They are also, as you’re probably quite aware, more or less screwed. In the Seychelles, for example, human activities and climate change have left corals bleached. Over fishing has caused fish stocks to drop. Biodiversity is in danger. Some form of protection is needed, obviously. When marine areas are strategically protected, the entire ecosystems can bounce back.
What exactly does smart ocean conservation look like? I want to share with you a brilliant idea from The Nature Conservancy (TNC). They’ve realized debt held by island and coastal nations is the key to achieving their conservation goals. TNC’s idea is to restructure this debt to generate the funds and political will to protect corals and fisheries.
This is how the work gets done. Step one: negotiate the deal. A coastal nation commits to protect at least 30% of its ocean areas. In exchange, TNC brings investors, public funders and international development organizations to the table to restructure a portion of the nation’s debt, leading to lower interest rates and longer repayment periods. Step two: create a marine plan. TNC works with marine scientists, government leaders and local stakeholders to create a detailed conservation plan that integrates the needs of the ocean with the needs of the people. Step three: activate for longevity. TNC establishes an independently operated conservation trust fund. The savings from the debt restructure goes into it to support new marine protected areas. The trust guarantees the government is responsible.
Could this plan work? It already has. In 2016, TNC helped create a national conservation plan in the Seychelles by restructuring $22 million of the government’s debt. And in exchange, the government agreed to protect 30% of its marine areas. Today, the Seychelles is on track to protect 400,000 square kilometers of ocean. That’s an area roughly the size of Germany. This success is making other governments take note. Many want to be part of this. Undeniably, with this approach, everyone wins. Government, local citizens, funders and most importantly, our oceans. So in fact, we all win.
1. What does the underlined word “screwed” probably mean in paragraph 1?| A．Protected. | B．Maintained. | C．Destroyed. | D．Ignored. |
| A．The governments can use the funds freely. |
| B．TNC only takes into account how the idea profits coastal nations. |
| C．Many coastal nations can afford ocean conservation independently. |
| D．The restructured debt will greatly help achieve marine conservation goals. |
| A．To show the effectiveness of TNC’s idea. |
| B．To promote TNC’s idea of restructuring debt. |
| C．To stress the importance of marine protection. |
| D．To explain the influence of marine protection. |
| A．Ah, earth’s oceans | B．An all-win idea for coral protection |
| C．A practical proposal for Marine Protection | D．Harm caused by human activities to oceans |
【推荐1】Learning, Fast and Deep
Over the past five years researchers in artificial intelligence have become the rock stars of the technology world. A branch of AI known as deep learning, which uses neural(神经的) networks to scan through large volumes of data looking for patterns, has proven so useful that skilled practitioners can command high six-figure salaries to build software for Amazon, Apple, Facebook and Google.
The standard route into these jobs has been a PhD in computer science from one of America’s top universities. Earning one takes years and requires a personality suited to academia, which is rare among more normal folk.
That is changing.
Last month fast.ai, a non-profit education organization based in San Francisco, kicked off the third year of its course in deep learning. Since its foundation it has attracted more than 100,000 students around the globe from India to Nigeria. The course and others like it, come with a simple idea: there is no need to spend years obtaining a PhD in order to practise deep learning. Creating software that learns can be taught as a craft, not as a high intellectual pursuit to be undertaken only in an ivory tower. Fast.ai’s course can be completed in just seven weeks.
To make it accessible to anyone who wants to learn how to build AI software is the aim of Jeremy Howard, who founded fast.ai with Rachel Thomas, a mathematician. He says school mathematics is sufficient. “No. Greek. Letters,” Mr. Howard intones, pounding the table with his fist for punctuation.
Some experts worry that this will serve only to create a flood of unreliable AI systems which will be useless at best and dangerous at worst. In the earliest days of the Internet, only a select few nerds, namely computerholics with specific skills, could build applications. Not many people used them. Then the invention of the World Wide Web led to an explosion of web pages, both good and bad. But it was only by opening up to all that the Internet gave birth to online shopping, instant global communications and search. If Mr. Howard and others have their way, making the development of AI software easier will bring forth a new crop of fruit of a different kind.
1. What can we learn about deep learning?| A．It replaces artificial intelligence. |
| B．It attracts rock stars to practice. |
| C．It scans patterns for large companies. |
| D．It helps technicians to create software. |
| A．ensures one to obtain a PhD | B．teaches craft in ivory tower |
| C．offers a course in deep learning | D．requires weeks to apply |
| A．easy | B．difficult |
| C．interesting | D．boring |
| A．it is quite reliable for anyone to grasp artificial intelligence |
| B．the Internet has brought forth a flood of useless AI systems |
| C．opening up to all leads to instant global search and online shopping |
| D．simplifying software development may result in unexpected outcomes |
【推荐2】Famous Scientists
Scientific discoveries over the centuries have helped shape the way we live today. Without pioneering scientists working towards cures for diseases, new inventions, and better ways to do things, life today would be different. Here are some of the most famous scientists, who have made important contributions to our everyday lives.
Hippocrates
Nationality: Greek
Known for: Father of Medicine
He was credited with writing the Hippocratic Oath that today’s medical professionals still follow in their practice. He had the theory of the vapors, which stated that many diseases were the result of a bad diet.
Aristotle
Nationality: Greek
Known for: Theory of Three Psyches, Scientific Method
He wrote about many scientific topics, including biology, physics and zoology. His ideas helped shape western scientific thoughts into the Renaissance until they were replaced with Newtonian physics.
Archimedes
Nationality: Greek
Known for: Archimedes Principle, Archimedes Screw
He was an astronomer, a scientist, and a physicist with several inventions to his name. He created a formula (公式) to calculate the area of the underside of a parabola (抛物线). He also designed many ancient machines.
Galen
Nationality: Roman
Known for: Father of Medicine
Galen was best known as Galen of Pergamon. He was a famous philosopher and surgeon among the Romans. His works contributed greatly to the knowledge of pharmacology (药物学), logic and philosophy.
1. Which Greek scientist contributed much to medicine?| A．Galen. | B．Aristotle. |
| C．Archimedes. | D．Hippocrates. |
| A．He influenced western scientific thoughts. |
| B．He designed lots of ancient machines. |
| C．He invented many chemicals. |
| D．He produced the theory of the vapors. |
| A．Having good luck in the field of science. |
| B．Making important contributions to science. |
| C．Writing many poems about science. |
| D．Experiencing many difficulties. |
【推荐3】Last summer, I had to stay in the room during the period of my recovery from cancer after the operation. It was unexpected that life highlighted everything that I might tend to take for granted in the normal course.
On the first morning, my children presented me a coffee pot. I liked to begin the day with a cup of coffee and was eager to try the pot.
When I made coffee, it spilled out over the whole table. Fortunately, nobody was there to see my embarrassed look! I kept trying, but each morning would see me wiping up the coffee. Then I realized that if I poured very slowly there would be no spilling.
This was at first a very painful experience. My normal practice was to rush through breakfast so that I could get on with my day. But at that moment I learned not only to pour slowly but to enjoy the experience: the smell, the taste, and the stillness of a new day.
It helped me to reflect upon whether there were other areas of my life 1 was rushing through. Most of life, it seemed. Strangely, those we consider loved ones may go of radar(雷达)when we would expect them to enquire about our well-being. However, others we seldom keep in touch with came into our lives suddenly, full of concern, well-meaning advice and love.
After the recovery period, I started to leave extra time to do even the most ordinary tasks. When shop owners would apologize for keeping me waiting, I would say, "Not a problem, I'm not in a hurry." Even hanging out washing became pleasurable when a couple of extra minutes of standing still, and listening to the birds singing in the trees around me became part of my routine.
Besides, one of my favorite experiences living in the inner city for many years was sitting on the front doorstep of our home spending time with strangers. We sat on the steps, each of us with a cup of coffee in our hands, listening to each other's stories. It was one of the warmest things about living in a busy city.
1. What was the author's life like before the time of recovery from the illness?| A．Awkward. | B．Relaxing. |
| C．Hurried. | D．Thrilling. |
| A．By pilling coffee over the table. | B．By buying a new pot. |
| C．By chatting with the strangers. | D．By pouring coffee slowly. |
| A．She had more time for reflecting on her past. |
| B．She found joy in ordinary daily activities. |
| C．She became impatient with any shop owner. |
| D．She liked listening to mysteries in busy cities. |
| A．To tell people how to make coffee tasty. |
| B．To advocate enjoying slow-paced life. |
| C．To show the gift from her children. |
| D．To recommend making friends with others. |
【推荐1】Welcome to our full-hotel hotel for dogs and cats. Here your cats can rest easy in comfortable quarters (住处)and dogs can enjoy playtime, salon services, training classes and more!
Accommodations Standard Guest Rom An open space that's cleaned daily and furnished with comfortable bedding Private Suite Large suits (套房) separated from the standard rooms for a more peaceful, private environment and they are perfect for multiple family pets. Rooms are cleaned daily and feature a raised cot (小床) and TV tuned to pet-themed shows. Kitty Cottage Cat cottages are kept separate from dog guest accommodation and they are cleaned daily. Boarding two cats? Cottages with connecting doors are available. Meals We serve meals for free. If you're bringing meals from home, please portion (分配) them into disposable (一次性的) sealed bags marked with your pet's name. Want to surprise your pet with a tasty snack? We also have treats and doggie ice cream available for purchase. Comforts Our cozy rooms and private suites are stocked with comfortable bedding but please feel free to bring your pet's bed, blanket and toys to make them feel even more at home. |
Boarding requirements Vaccinations Vaccinations (疫苗) must be administered at least 48 hours prior to arrival under the guidance of a licensed veterinarian (持证兽医). However, we prefer that vaccinations should be administered 10 to 14 days before check-in to make sure maximum efficiency. Witten proof is required. Fleas & Ticks In addition to vaccinations, all pets should be flea and tick (虱子) free. Overnight "guests" with signs of fleas And/or ticks will not be allowed to check in. |
Additional Requirements All PetsHotel guests must be over four months old before we can offer hospitality. |
①clean and comfortable quarters
②salon services and training classes
③free meals for pets
④tick and flea clean-up service
| A．①②③ | B．①③④ | C．①②④ | D．②③④ |
| A．Private suites in PetsHotel are only for guests with many pets |
| B．PetsHotel offers delicious snacks for pet guests for free. |
| C．Toys are not allowed into PetsHotel. |
| D．PetsHotel only accommodates pets aged four months and above. |
| A．On the website of an animal protection group. | B．In the Life section of a newspaper. |
| C．On the leaflet of a hotel for pets. | D．On the announcement board of a pet clinic. |
【推荐2】Food Allergy and Special Dietary Needs
Our District will have a School Nutrition Program which shall provide individualized menus or food preparations for students who are unable to have the meals normally served at our school as required by their individual education plan (IEP) or health plan. Read the following information carefully so that we are on the same page.
PARENTAL ASSISTANCE
You will be asked to:
•Inform the school principal of any food allergy or special dietary needs related to a disabling condition or medical necessity.
• Provide medical information from a District-approved recognized medical authority(RMA).
• Offer updated medical information as requested by the District.
• Participate in any meeting or discussion regarding the students’ meal plan.
• Notify the school of any change related to the food allergy or special dietary needs.
SCHOOL SITE RESPONSIBILITIES
• Find out children requiring special dietary change.
•The principal shall refer students with special dietary needs (o special services as required by law.
• The nurses shall make teachers and students aware of allergy alert identification. Prevention needed related to field trips and classroom parties, strategies and other issues necessary to promote student safety.
• Monitor and update the IEP or health plan as needed.
DISTRICT NUTRITION SERVICE RESPONSIBILITIES
•We will provide food item services and individualized menus for students according to medical need. Menus will not be changed because of personal preference.
• We will train school medical staff on how to react to food allergies and food-related emergencies and how to change menus.
• We will maintain special dietary information on each student identified as having special dietary needs and update this information as needed.
1. Who will probably be served with an individualized menu?| A．All disabled students. |
| B．Each unhealthy student. |
| C．Students with a food allergy. |
| D．Students with a taste preference. |
| A．RMA is involved in planning students' meals. |
| B．Students are required to update the health plan. |
| C．The teachers train students to identify allergies. |
| D．The District provides services and specific instructions. |
| A．A clinic notice. | B．A guideline for parents. |
| C．A medical journal. | D．A school yearbook. |
【推荐3】 “Today, technical innovations dominate our everyday life in many areas. New technologies, however, always are associated with risks-and these are also seen by laymen,” says Christoph Böhmert, first author of the recently published study and researcher of the Science Communication Group of KIT's Institute for German Studies. “It is crucial to enable adequate communication between science and society, which does not only consider scientific findings, but also concerns of the population.” The study clearly showed that communication of risks may be complicated sometimes. Information on efficient precautions was found to lead to an increased risk perception by the recipients of the information.
In their study, the researchers analyzed communication about a technology that has become indispensable in our life-mobile communications and the electromagnetic fields(电磁场) on which it is based. All over the world, radiation protection authorities, such as the German Federal Office for Radiation Protection, communicate the current state of research into risks of electromagnetic fields as follows: Investigations made and all findings obtained so far do not allow any conclusions to be drawn with respect to mobile communications being a risk for human health. But, the experts continue, there still are knowledge gaps as regards long-term impacts. Then, measures are recommended to reduce exposure of the individual to electromagnetic fields.
It had been known from previous studies already that information on precautions may increase worries. It had been suspected that people conclude from the recommendation of precautions that there really is a risk. This effect was not confirmed by the recent study. The scientists rather attributed the increased worries to a lack of knowledge about the propagation(传播) of electromagnetic fields.
Within the framework of the study, the recommended precautions were submitted to 1717 Australians, together with one of six information brochures providing scientific background information. When test persons were given not only the recommendations, but also explained why observation of these tips strongly reduces their exposure to electromagnetic fields, worries increased. For example, scientists explained to the test persons that telephone conversations with a headset largely reduce exposure. When a mobile phone is located ten centimeters instead of just one centimeter away from the ear, the electric power absorbed by the ear is about one hundredth of the initial value. Hence, their own mobile phone usually causes an exposure that by far exceeds that of mobile communications stations that are generally referred to as “cellphone towers”. While the scientists wanted to explain the effectiveness of precautions, test persons mainly considered this information to be an indication of their mobile phone-not the transmission towers-being dangerous. As a result, they perceived increased risk potentials for telephone conversations with their mobile phones.
“The study reveals that messages on precautions and information are a double-edged sword in terms of subjective risk perception. Their use should be far better understood,” Boehmert says.
1. Which of the following statements is TRUE according to the passage?| A．Adequate information on efficient precautions can relieve the concerns of the public. |
| B．Mobile communications definitely do harm to people's health in the long run. |
| C．Information about technologies and their risks may have undesired side effects. |
| D．Observation of the precautions can help reduce the concerns of the public. |
| A．enable the users to know better of science and technology |
| B．produce new electric products with a lower radiation value |
| C．provide the public with less information on effective precaution |
| D．inform the public about the potential risks with more patience |
| A．introduction | B．intention |
| C．recommendation | D．prevention |
| A．Science and Technology: A Double-edged Sword |
| B．Technical Innovation: Worries and Information |
| C．Science and Technology: Security Tips for Users |
| D．Technical Innovations: Effectiveness of Precautions |
