51、根据以下内容回答51-70题：
It is Dredicted that there will be four scientific breakthroughs in the 21 st centruy．
We wiuknow where we came from．Since the l920s，scientists have known the universe is expanding，which means it must have started at a definite time in the past．They even have de-veloped theories that give a detailed picture of the universe from the time it was a fraction of a second old to the present．Over the next couple of decades，these theories will be improved by data from powerful new telescopes．
We will find out the genetic code and conquer cancer．In l9th century operas，when the heroine coughs in the first act，the audience knows'she will die of tuberculosis in the third act．But thanks to 20th century science，the once deadly disease now means nothing more serious than taking some pills．As scientists learn more about the genetic code and the way cells work，many serious desease--cancer．will become less threatening．
We will live longer，probably up to 1 20 years．If the normal aging process is basically a fierce．invisible contest in our ceus——a contest between damage to our DNA and our ceils’abili-ty to repair that damage，gre{at progress around．But before we push scientists to do more，we should consider：do we really want to live in a world where no one grows old?
We will haye a hrain road map．This is the real final frontier of the 21 st century．The brain is the most complex system we know．It contains about l00 billion nerve cells，each con-nected to as many as l000 0thers．Early in the 21 st century，progress in science will make it Dossible to produce detailed images of the nerve cells in operation．We will be able to say with certainty which ones are working when you read or think about a word．
Jadging from the second paragraph，the writer thinks of present theories about the uinverse as __________．
A．perfect
B．imperfect
C．groundless
D．complicated


52、The writer uses the example of the fate of heroines in l9th century operas to show that
A．science provides mediical solutions
B．tuberculosis will be a curable disease
C．science influences literary development
D．the genetic code helped cure tuberculosis


53、It can be inferred form the passage that people become old when__________ ．
A．cell daamage is fierce and invisible
B．cell contests are too fierce to control
C．cell repair is slower than cell damage
D．cells stop repairing damage done to them


54、 With a brain road map．we will be able to
A．know how particular ceHs work
B．store detailed images in our brain
C．find out the number of brain cells
D．operate on patients with brain disease


55、 The best title for the passage may be__________ ．
A．We Can Live Longer in the 21 st Century
B．Cancer to Be Conquered in the 21 st Century
C．The Final Frontier of the 21 st Century
D．Scientific Breakthrough of the 2 1 st Century


56、根据以下内容回答56-75题：
A third of Britains are overweight，states a report published in January by the Royal
Collgeg of Physicians，the resuh of an l8-month-long study．About five percent of children weigh too much，and are likely to stay that way for life；in the mid-twenties age group the pro-portion of fat people rises to a third，and of the middle-aged population half are overweight．
Fat people risk severe health problems，says the report，including high blood pressure，breathlessness．and various forms of heart disease．Smoking is particularly risky for overweightpeople．
The safest way to lose weight is to eat cereals，bread，fruit and vegetables，and cut down on fatty meats，butter and sweet foods，Bad diets do far more harm than good slimming ma-chines that vibrate muscles have not been proved useful．Saunas(桑拿浴)merely remove a little body water，and health farms，says the report，serve as expensive holidays．
Exercise is most important to health，the report emphasizes；though it doesn’t necessarily reduce weight，it maintains the correct proportion of body fat to body muscle．And it isn’t only for the young；from middle age a minimum of 20 minutes of general physical jerks should be practiced three times a week．
The report advocates several public health measures to combat the high prevalence of over-weight in this country．They include an increase of tax on alcohol to reduce its increasing，and dangerously fattening，consumption；and the provision of more sports facilities by local authori-ties．Britain’S doctors，the report concludes，must learn to be more sympathetic and specific in their advice to the overweight，encouraging a change in eating habits on a long-terra basis，and taking into account the many often complex reasons why fat people are fat．
The passage mainly talks about__________ ．
A．the cause of Britain’S overweight
B．how to avoid getting overweight
C．Britain’S overweight problem
D．the relations between overweight and health problems


57、According to the report，a person is most likely to stay fat for the whole of his life if he
A．gets fat in the twenties
B．gets fat in his middle age
C．is born fat
D．gets fat when he is child


58、The report suggests that exercise__________ ．
A．is a way to reduce weight
B．sometimes increase weight
C．is a sure way to keep one healthy
D．can convert fat to muscle


59、The report points out that drinking too much alcohol__________ ．
A．will also cause one to get fat
B．wjll cause one to do 1ess sports
C．wiumake one forget the fact that he is fat
D．will lead one to bad eating habits


60、Britain’S doctors，when treating the overweight，should__________ .
A．encourage a long—term diet for everyone
B．be more considerate and give detailed advice
C．first consider why so many people arefat
D．do aU of the above