black

大学试题答案(课后习题答案)

单项选择题

根据下列文章,请回答 36～40 题。
Eat to Live
A meager(不足的)diet may give you health and a long life，but it's not much fun and it might not even be necessary．We may be able to hang on to most of that youthful vigor even if we don’t start to diet until old age．
Stephen Swindler and his colleagues from the University of California at Riverside have found that some of an elderly mouse’s liver genes can be made to behave as they did when the mouse was young simply by limiting its food for four weeks．The genetic rejuvenation(恢复活力)won’t reverse other damage caused by time for the mouse，but could help its liver metabolize(新陈代谢)drugs or get rid of toxins(毒素)．
Swindler’s team fed three mice a normal diet for their whole lives，and fed another three on half-rations．Three more mice were switched from the normal diet to half-feed for a month when they were 34 months old——equivalent to about 70 human years．
The researchers checked the activity of 11，000 genes from the mouse livers，and found that 46 changed with age in the normally fed mice．The changes were associated with things like inflammation and free radical(自由基)production—probably bad news for mouse health．In the mice that had dieted all their lives，27 0f those 46 9enes continued to behave like young genes．But the most surprising finding was that the mice that only started dieting in old age also benefited from 70 per cent of these gene changes．
“This is the first indication that these effects kick in pretty quickly,” says Huber’ Warner from the National Institute on Aging near Washington，DC．
No one yet knows if calorie restriction works in people as it does in mice，but Spindler is hopeful．“There’s attracting and tempting evidence out there that it will work，”he says．
If it does work in people，there might be good reasons for rejuvenating the liver．As we get older，our bodies are less efficient at metabolizing drugs，for example．A brief period of time of dieting。says Spindler,could be enough to make sure a drug is effective．
But Spindler isn’t sure the trade—off(交换)is worth it．“The mice get less disease，they live longer, but they’re hungry,” he says．“Even seeing what a diet does，it's still hard to go to a restaurant and say：‘I can only eat half of that’．”
Spindler hopes we soon won’t need to diet at all．His company, Life Span Genetics in California，is looking for drugs that have the effects of calorie restriction．
第 36 题 According to the passage，which of the following is NOT true?
A．Eating less than usual might make US live longer．
B．If we go on a diet when old，we may keep healthy．
C．Dieting might not be needed．
D．We have to begin dieting from childhood．

A.We
B.
Stephen
C.The
D.
Swindler’s
E.Three
F.
The
G.The
H.In
I.But
J.
“This
K.
No
L.“There’s
M.
If
N.As
O.A
P.
But
Q.“The
R.“Even
S.”
Spindler
T.His
U.Eating
V.
B．If
W.
C．Dieting
X.
D．We
相关考题

未知题型 Acid rain is a very serious air and water pollution problem. Many people feel-that it is the most serious pollution problem that we now face. Scientists say that plant and animal life in thousands of lakes in the United States and Canada has already been destroyed by acid rain. Acid rain forms in the upper atmosphere. There, sulfur dioxide and nitrogen oxides mix with water vapor. They mix with water vapor to form. sulfuric acid and nitric acid. When the vapor condenses and rain falls, the acids fall with it. Every time acid rain falls in a lake, the level of acid in the lake rises. Over time, it can rise to the point at which plants and insects cannot survive. Without plants, which supply oxygen, and insects, which supply food, fish die. The lake becomes a dead lake. The problem of acid rain has greatly increased in the last few years. Most of the blame for acid rain has been placed on industries. However, some people feel that ineffective air pollution laws are also to blame for the acid rain problem. A few years ago, many cities and states passed local air pollution laws. The laws were written to impr9ve the air quality in the cities and states. However, the laws usually didn't say anything about the amount of pollution that an industry could pump into the air. Industries found a way to meet the new pollution laws without reducing the amount of pollution they released. They met the new standards by building taller smokestacks. With the taller smokestacks, air pollutants were released higher up into the atmosphere. The wind carried them far away from the polluting factory. To the people near the factory, the air seemed cleaner. However, the pollution that they once got was now coming down hundreds of miles away in the form. of acid rain.Which of the following is TRUE about acid rain?A．It is acknowledged by scientists to be the most serious pollution problem that human beings now face.B．Many endangered species are on the verge of extinction because of acid rain.C．Acid rain is composed of sulfur dioxide and nitrogen oxides mixed with water vapor found in the upper atmosphere.D．Acid rain is mostly found in the United States and Canada.

未知题型 建立健全党中央统一领导，党委(党组)全面监督，_______， _______，党的基层组织日常监督，党员民主监督的党内监督体系。

单项选择题 根据下列材料请回答 31～35 题：Centers of the Great European CitiesThe centers of the great cities of Europe are meeting places by tradition-People gather there to drink coffee and chat late into the night.A mixture of locals and tourists make for an exciting，metropolitan atmosphere.Squares，plazas(广场)and arcades(拱廊)form. the heart of Europe’s cities.Venice in Italy has the Piazza San Marco—a beautiful square surrounded by shops，churches，restaurants and caf6s.In Barcelona，Spain，LaBosqueria is a lively market with hundreds of stalls selling all kinds of goods.London’s Covent Garden is filled with fruit and vegetable stalls by day and musicians，acrobats(杂技演员)and artists by night.The government buildings at the center of many cities often are architecturally impressive.In London，they serve as a beautiful backdrop(背景)to the coffee tables that line the streets and the banks of the Thames.These vibrant(有活力的)hearts are the product of centuries of evolution，social historian Joel Garreau told US News and World Report recently.“The reason people think Venice is so great today is you don’t see all the mistakes，”said Garreau-“ Those have all been removed.”Most European cities were laid out before the invention of the car, so bars.restaurants and cafes were near to，people’s homes.Today，the focus of many Europeans’life has moved away from the centers.They live in the suburbs and outskirts，driving to supermarkets to get their supplies.But on a continent where people treasure convention，there are still those who hold onto traditional ways，living and shopping locally.These people.together with tourists，provide the city centers with the reason for existence.Coffee culture plays a part in keeping these city centers flourishing .this is Particularly true of Paris whose citizens are famous enthusiastic conversationalists this skill is developed over many hours spent chatting over espressos(浓咖啡)and cigarettes.Religion also plays a role in developing sociable atmosphere.People In Roman Catholic countries used to visit the Church on an almost daily basis.Entire communities would gather in the same building and then move out to the markets.cafes and bars In the surrounding streets.An enormous example of this relationship between church and society is the Duomo。The huge marble cathedral in Florence，Italy IS surrounded by bakeries and coffee shops，and caters not only to the tourist crowds，but also the local community. 第 31 题 It can be inferred from the first paragraph that each big city in EuropeA．has many large squares.B．has many very magnificent sky-scrapers.C．draws tourists in large numbers every yearD．has a center where tourists meet their spouses.

All Rights Reserved 版权所有©在线考试题库网(zxkao.com)

备案号：湘ICP备14005140号-7

经营许可证号：湘B2-20140064