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2024年全國(guó)英語(yǔ)等級(jí)考試（PETS）五級(jí)經(jīng)典試題及答案一,更多相關(guān)資訊請(qǐng)繼續(xù)查看易考吧全國(guó)外語(yǔ)水平考試內(nèi)容
1). Telegrams have just passed into history in America，following the announcement by Western Union，once the colossus of the industry，that it was discontinuing its telegram service at the end of January.Yet in a sense，the technology pioneered by Samuel Morse has been reborn with a modern twist，in the form of text messages sent between mobile phones.For years，foreigners have wondered why Americans，usually at the vanguard of technological adoption，were so reluctant to embrace texting.But now they have adopted the technology with enthusiasm.What happened？■America’s apathy towards texting was easy to explain.Voice calls on mobile phones are cheaper than in other countries，which gives cost-conscious users less incentive to send texts instead； several different and incompatible wireless technologies are in use，which made sending messages from one network to another unreliable or impossible； and texting was often an additional service that subscribers had to sign up for.As a result，the number of messages sent per subscriber per month was just over seven in December 2002，compared with a global average of around 30.■But things have since changed，with that figure rising to 13 in December 2003，26 in December 2004，and 38 in June 2005，the most recent date for which figures are available from the Cellular Telecommunications Industry Association，an industry body.So America has now overtaken Germany，Italy and France in its enthusiasm for texting.■There are several reasons for this.“We’ve had that penetration of the youth market，” says Brian Modoff，an analyst at Deutsche Bank.“We didn’t have that until a couple of years ago.” Family calling plans and other new tariffs have put phones in the hands of more young people，who are more likely to adopt texting.There have also been technical changes： GSM，the text-friendly wireless technology used in Europe，has become far more widespread in America as operators have switched customers to it from older technologies，notes John Tysoe of The Mobile World，a consultancy.Interconnections between networks have improved too.■But perhaps the most surprising factor is the role of reality television-and in particular，“American Idol”，a talent show in which viewers phone in to vote for competing singers.In 2004，13.5 million viewers cast votes by text messages-nearly half of them using the technology for the first time.Last year the number of votes was 41.5 million.“That upward arc is a fair indicator for the acceleration in growth of texting in general，” says Mark Siegel of Cingular，America’s biggest mobile operator.Even when viewers do not vote by text themselves，such programmes raise awareness of texting in general，says Mr.Modoff.Whatever you think about the music，“American Idol” has undoubtedly helped Americans to discover a valuable new talent.What is the text mainly about？( )
A.Prediction of future trends in America
B.Comparison of America and Europe’s interest in a new technology
C.Analysis of reasons for a trend in America
D.Analysis of reasons for America’s lack of interest in a new technology

正確答案：C
2). It takes only a tiny magnetic field to see clear through a person’s head，a new study shows.A method called ultra-low field magnetic resonance imaging (MRI) has captured its first，blurry shots of a human brain，revealing activity as well as structure.■MRI scanners image the human body by detecting how hydrogen atoms respond to magnetic fields.They typically require fields of a few tesla-about 10，000 to 100，000 times stronger than the Earth’s magnetic field.The powerful magnets necessary make scanners pricey and also dangerous for people with metal implants.■The new device hits a sample with a 30 millitesla magnetic field，about 100 times weaker than is normally used in MRI.The device then uses a 46 microtesla magnetic field-about the same as the Earth’s magnetic field-to capture images of the sample.■The first target for the device was the head of lead researcher Vadim Zotev of Los Alamos National Laboratory in New Mexico，US.■“The cost of MRI can be reduced dramatically，” Zotev says.The new set-up uses several ultrasensitive sensors called superconducting quantum interference devices (SQUIDs)，which have to be kept at very low temperatures.“The most expensive part of our system is the liquid helium cryostat，which costs about $20，000，” Zotev adds.■Ultra-low field MRI scanning was first performed with a single SQUID in 2004 by a group led by John Clarke at University of California，Berkeley，US，but this only allowed objects about the size of an apple to be scanned.The new device uses seven SQUIDs and can scan much larger objects.■MRI machines in the clinic today require a patient to be slotted into a long，cylindrical tube.Ultra-low field MRI machines can be much more open.“Microtesla MRI is more suitable for surgical environment than high-field MRI，” Zotev says.“Some medical equipment can be conveniently placed inside [the scanner]，” including surgical robots，Zotev says.■Today’s MRI machines can also be problematic for people with metal implants，since intense magnetic fields can move or heat them causing damage to surrounding tissue.■Experiments show that ultra-low field MRI can image materials even when metal is placed near the magnets.■However，ultra-low field MRI hasn’t been tested on animals or people with metal implants yet.“It would be wrong to claim that it is absolutely safe，” Zotev says.■Since the new device also doubles as magnetoencephalography (MEG) machine，by picking up the feeble magnetic fields from electrical activity in the brain，it could perhaps let surgeons more easily identify areas of the brain with abnormal activity，such as in epilepsy.■“This is the main advantage of the new set-up，” Clarke says.“It’s a nice step forward.”The ultra-low field MRI captures images by using fields about ( ).
A.100 times weaker than is normally used in MRI
B.10，000 to 100，000 times stronger than the Earth’s magnetic field
C.100 times weaker than the Earth’s magnetic field
D.the same as the Earth’s magnetic field

正確答案：D
3). Married mothers who also hold jobs，despite having to juggle career and home，enjoy ( ) health than their underemployed or childless peers.Data from a long-term study launched in the UK in 1946 shows that such working moms are the ( ) likely to be obese ( ) middle age and the most likely to report generally good health.And this result cannot be explained simply ( ) the healthiest women take on the most.■Epidemiologist Anne McMunn of University College London drew more than 1，400 female ( ) from a study of 5，362 Britons born during the first week of March 1946.Followed ( ) their lives，including face-to-face interviews at ( ) 26，36，46 and 53，the women provided data from both their own views of their health as well as ( ) measures such as body-mass index.By assessing both ( ) and objective information，the researchers hoped to discover ( ) working moms undertook such multitasking because of their inherent ( ) or achieved good health because of their multiple roles.■Of the 555 working mothers，only 23 percent proved obese ( ) age 53，compared to 38 percent of the 151 full-time homemakers，( ) also averaged the highest body-mass index of all six categories of ( ).rounded out by single working mothers，the childless，multiply-married working moms and intermittently-employed married mothers.In ( ) ，full-time homemakers reported the most poor health，( ) by single mothers and the childless.■Of course，the data do not show ( ) working moms are healthiest but the women’s view of their own health at 26 did not correlate ( ) whether they undertook ( ) careers and families，seeming to discount a definitive role for good health in determining a woman’s choices.Working correlated with low body mass ( ) all groups，including single moms and childless women.( )

正確答案：ages

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