*第三十八篇
Longer Lives for Wild Elephants
Most people think of zoos as safe places for animals，where struggles such as difficulty finding food and avoiding predators don't exist. Without such problems,
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animals in zoos should live to a ripe old age．
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But mat may not be true for the largest land animals on Earth. Scientists have known that elephants in zoos often suffer from poor health．They develop diseases，joint problems and behavior changes．Sometimes．they even become infertile．or unable to have babies．
To learn more about how captivity affects elephants, a team of international scientists compared the life spans of female elephants born in zoos with female elephants living outdoors in their native lands．Zoos keep detailed records of all the animals in their care，documenting factors such as birth dates，illnesses，weight and death．These records made it possible for the researchers to analyze 40 years of data on 800 African and Asian elephants in zoos across Europe．The scientists compared the life spans of the zoo．born elephants with the life spans of thousands
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of female wild elephants in Africa and Asian elephants that work in logging camps，over approximately the same time period．
The team found that female African elephants born in zoos lived an average of l 6.9 years．Their wild counterparts who died of natural causes lived an average of 56 years——more than three times as long．Female Asian elephants followed a similar pattern．In zoos, they lived l 8．9 s years, while those in the logging camps lived 41.7 years．
Scientists don't yet know why wild elephants seem to fare so much better than their zoo-raised counterparts．Georgia Mason，a biologist at the University of Guelph
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in Canada who led the study, thinks stress and obesity may be to blame．Zoo elephants don't get the same kind of exercise they would in the wild，and most are very fat．Elephant social lives are also much different in zoos than in the wild，where they live in large herds and family groups．
Another finding from the study showed that Asian elephants born in zoos were more likely to die early than Asian elephants captured in the wild and brought to zoos．Mason suggests stress in the mothers in zoos might cause them to have babies that are less likely to survive．
The study raises some questions about acquiring more elephants to keep in zoos．While some threatened and endangered species living in zoos reproduce successfully and maintain healthy populations，that doesn't appear to be the case with elephants．\，zoos al e net consumers of elephants，not net producers，\．
词汇：
Predator n．食肉动物 Ripe adj．成熟的
Infertile adj．不生育的 Captivity n．监禁；束缚
Fare v．过活，生活
Obesity adj．过度肥胖；肥胖症
注释： 1．1ive to a ripe old age：这是一种固定用法，意思是live to an age that is considered to be very old(长寿，高寿)。
2．be true for：或者be true of：对??适用。短文中第二段第一句：But that may not be true for the largest land animals on Earth．这里，作为主语的that指的是第一段所陈述的内容。这个句子要传达的意思是：动物园对其他动物来说是一个安栖之地，而对大象来说却不然。
3．logging camps：伐木场。Loggin9作为名词，意思是：伐木业。
4．stress and obesity may be to blame：压力和肥胖是问题的根源。be to blame：该受责备，应承担责任。
练习：
1．According to the first two paragraphs，unlike other zoo animals，zoo elephants A．have difficulty eating food． B．1ive to a ripe old age．
C：are not afraid of predators． D．develop health problems．
2．Which of the following about the international scientists' research on the life spans of elephants is NOT true? (See paragraph 3)? A．They compared zoo elephants with wild elephants．
B．They kept detailed records of all the elephants in their care． C．They analyzed the records of the elephants kept in zoos．
D．The zoo-born elephants they studied are kept in European zoos． 3．What do the scientists find in their research?
A．Female elephants live longer than male elephants．
B．Female zoo elephants live longer than their wild counterparts．
C．Female zoo elephants die much earlier than their wild counterparts． D．Elephants in zoos and those in the wild enjoy the same long life spans． 4．What are the possible causes of stress and obesity zoo—raised elephants generally suffer from?
A．They do not like living in herds． B．They do not get enough exercise．
C．They do not live with their families． D．Both B and C．
5．Which of the following does the author suggest in the last paragraph? A．It may not be a wise policy to keep elephants in the zoo． B．Elephants are no longer an endangered species．
C．Zoo-born elephants should be looked after more carefully． D．Zoos should keep more animals except elephants．
答案与题解：
1．D短文的第一段告诉我们，人们通常认为动物园内的动物没有猎食的困难，也不受其他 猎食动物的威胁，所以一般寿命较长。但第一段并没有提及大象。第二段则说，动物园内的大象却不然，它们面临很多健康问题。所以，除了D以外，其他选项均不符合这两段内容。
2．B 第三段告诉我们，动物园，而不是这些研究人员，保存了所有园内动物的详细相关信息。所以应该选择8。其他三个选项均能在该段中找到相关内容。
3．C短文的第四段提供了答案。该段告诉我们，野生的雌性大象的平均寿命是动物园里的雌性大象平均寿命的3倍还多。
4．D短文的第五段提供了答案。该段第三句的意思是：动物园里的大象不像野生大象那样活动，因此非常肥胖。他们也不像野生大象那样过着群居的生活，即live in herds and family groups。
5．A短文通篇陈述了大象在动物园内的生存问题，最后一段是全文的总结。该段第一句指出，对动物园大象的研究向人们提出了一个问题：是否应该将更多的大象关进动物园。该段还重复了第一、第二段的观点：其他动物在动物园能够很好地繁衍生息，而大象却不能。所以，A是正确选择。 B、C、D均没有在文中被提及。
野生大象寿命更长
人们通常认为动物园对于动物来说是安全的，因为他们没有猎食的困难，也不受其他肉食动物的威胁，所以动物园内的动物应该寿命较长。
但世界上最大的陆地动物却并非如此。科学家已经发现大象面临着很多健康问题，例如生病、关节问题和行为改变等，有时甚至会失去生育能力。
为了了解禁闭生活对大象的影响，一队国际科学家将在动物园出的雌象与生活在自然环境中的雌象的寿命进行了对比。动物园保留了所饲养动物的详细记录，包括出生日期、疾病、体重的死亡等因素。有了这些记录，研究人员能够分析全欧洲800头非洲象和非洲象历时40年的数据。科学家将动物园出生的大象与同一时间段的几千头非洲野生雌象、在伐木场劳动的亚洲象进行了寿命对比。
这些科学家发现，动物园出生的非洲雌象平均寿命是16.9年，而自然死亡的野生大象平均寿命是56年——是动物园大象的3倍多。亚洲雌象情况类似：动物园雌象寿命是18.9年，而伐木场雌象的寿命是41.7年。
科学家尚不清楚野生大象比动物园大象获得更好的原因。负责这一研究的加拿大圭尔夫大学生物学家乔治亚·梅森认为，压力和肥胖是问题的根源。动物园大象不像野生大象那样活动，因此非常肥胖。动物园大象的社会生活也很不同，不像野生大象那样过着群居的生活。
该研究的另一发现表明，在动物园出生的亚洲象比野外捕获后放入动物园的亚洲像死的要早。梅森认为动物园母象的压力可能导致小象成活率低。 对动物园大象的研究向人们提出了一个问题：是否应该将跟多的大象关进动物园。尽管有些濒危物种在动物园能够很好地繁衍生息、健康成长，大象却并非如此。梅森说，“动物园现在不是大象的纯粹生产者，二十纯粹消费者。”
+第四十五篇
Some People Do Not Taste Salt Like Others
Low—salt foods may be harder for some people to like than others，according
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to a study by a Penn State College of Agricultural Sciences food scientist．The research indicates that genetic factors influence some of the difference in the levels of salt we like to eat．
Those conclusions are important because recent，well—publicized efforts to
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reduce the salt content in food have left many people struggling to accept fare
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that simply does not taste as good to them as it does to others，pointed out John
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Hayes，assistant professor of food science，who was lead investigator 0n the study． Diets high in salt Can increase the risk of high blood pressure and stroke．That is why public health experts and food companies are working together on ways to help consumers lower salt intake through foods that are enjoyable to eat．This study increases understanding of salt preference and consumption． The research involved 87 carefully screened participants who sampled salty foods
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such as soup and chips，on multiple occasions，spread out over weeks．Test subjects were 45：men and 42 women, reportedly healthy，ranging in age from 20 t0 40 years．The sample was composed of individuals who were not actively modifying their dietary intake and did not smoke cigarettes．They rated the intensity of taste on a commonly used scientific scale，ranging from barely detectable to strongest sensation of any kind．
“Most of us like the taste of salt．However，some individuals eat more salt，both because they like the taste of saltiness more，and also because it is needed to block other unpleasant tastes in food,” said Hayes. “Supertasters, people who experience tastes more intensely, consume more salt than nontasters do. Snack foods have saltiness as their primary flavor, and at least for these foods, more is better, so the supertasters seem to like them more.” However, supertasters also need higher levels of salt to block unpleasant bitter tastes in foods such as cheese，Hayes noted．“For example，cheese is a wonderful blend of dairy flavors from fermented milk，but also bitter tastes from ripening that are blocked by salt，” he said．“A supertaster finds low-salt cheese unpleasant
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because the bitterness is too pronounced．”
Hayes cited research done more than 75 years ago by a chemist named Fox and a geneticist named Blakeslee，showing that individuals differ in their ability to taste certain chemicals．As a result，Hayes explained，we know that a wide range in taste acuity exists，and this variation is as normal as variations in eye and hair color．
“Some people，called supertasters，describe bitter compounds as being extremely bitter，while others，called nontasters，find these same bitter compounds to be tasteless or only weakly bitter．”he said．“Response to bitter compounds is one of many ways to identify biological differences in food preference because
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supertastin is not limited to bitterness． (476)
词汇：
Publicize v．引起公众对?的注意；(用广告)宣传
Dietary adj．饮食的；规定食物的 Ferment v．(使)发酵 Geneticist n．遗传学家 Acuity n．敏锐；尖锐
注释：
1．Penn State College of Agricultural Sciences：即Penn State University--College of Agricultural Sciences宾州州立大学农学院。Penn是Pennsylvania的缩写，是美国宾夕法尼亚州名。宾州州立大学建于1855年：在全国共有24个分校。在句中，Penn State College of Agricultural Sciences用作定语，修饰food scientist。
2．Well-publicized efforts to reduce the salt content in food：大力宣传减少食物含盐量的做法
3．1eft many people struggling to accept fare that simply does not taste as good to them as it does to others：使得许多人努力去接受适合其他人而不适合他们口味的食物。fare相当于food。
4．1ead investigator：研发项目负责人
5．?carefully screened participants who sampled salty foods as soup and chips．on multiple occasion，spread out over weeks：??经过仔细筛选的实验参与者，他们在几周内的不同时间里品尝了汤和薯条等含盐食物。
6．too pronounced：此处pronounced为形容词，意为very noticeable，conspicuous(明显的，显著的)。
7．supertasting：超重味感
练习：
1．In paragraph 2，John Hayes points out that
A．it is good to health to eat food without salt． B．many people reject low—salt food completely．
C．many people accept low—salt tasteless food reluctantly D．food with reduced salt tastes better． 2．The fourth paragraph describes briefly
A．how to select subjects and what to do in the research． B．how to identify supertasters and nontasters．
C．why to limit the number of subjects to 87 persons． D．why to select more male subjects than female ones． 3. The article argues that supertasters
A．1ike the；taste of saltiness to block sweet tastes in food． B．1ike snack foods as saltiness is their primary flavor．
C．consume less salt because they don t like intensive tastes． D．1ike to share salty cheese with nontasters．
4. Which of the following applies to supertasters in terms of bitter taste? A．They like bitterness in foods as well as saltiness．
B．They like high．salt cheese as it has intense bitter taste． C．They prefer high—salt cheese．which tastes less bitter．． D. They prefer high-salt cheese as it is good to health．