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At the base of a mountain in Tanzania's Gregory Rift, Lake Natron burns bright red, surrounded by the remains of animals that were unfortunate enough to fall into the salty water. Bats, swallows and more are chemically preserved in the pose in which they perished, sealed in the deposits of sodium carbonate in the water. The lake's landscape is bizarre and deadly—and made even more so by the fact that it's the place where nearly 75 percent of the world's flamingos (火烈鸟）are born.
The water is so corrosive that it can burn the skin and eyes of unadapted animals. Flamingos, however, are the only species that actually makes life in the midst of all that death. Once every three or four years, when conditions are right, the lake is covered with the pink birds as they stop flight to breed. Three-quarters of the world's flamingos fly over from other salt lakes in the Rift Valley and nest on salt-crystal islands that appear when the water is at a specific level—too high and the birds can't build their nests, too low and predators can move briskly across the lake bed and attack. When the water hits the right level, the baby birds are kept safe from predators by a corrosive ditch.
"Flamingos have evolved very leathery skin on their legs so they can tolerate the salt water," says David Harper, a professor at the University of Leicester. "Humans cannot, and would die if their legs were exposed for any length of time." So far this year, water levels have been too high for the flamingos to nest.
Some fish, too, have had limited success vacationing at the lake as less salty lagoons (泻湖) form on the outer edges from hot springs flowing into Lake Natron. Three species of tilapia (罗非鱼) thrive there part-time. "Fish have a refuge in the streams and can expand into the lagoons when the lake is low and the lagoons are separate," Harper said. "All the lagoons join when the lake is high and fish must retreat to their stream refuges or die." Otherwise, no fish are able to survive in the naturally toxic lake.
This unique ecosystem may soon be under pressure. The Tanzanian government has once again started mining the lake for soda ash, used for making chemicals, glass and detergents. Although the planned operation will be located more than 40 miles away, drawing the soda ash in through pipelines, conservationists worry it could still upset the natural water cycle and breeding grounds. For now, though, life prevails—even in a lake that kills almost everything it touches.
1
What can we learn about Lake Natron?
A.
It is simply uninhabitable for most animals.
B.
It remains little known to the outside world.
C.
It is a breeding ground for a variety of birds.
D.
It makes an ideal habitat for lots of predators.
本题答案：
A
B
C
D
参考答案：
A
系统解析：
推理判断题。首段第一句指出，在坦桑尼亚格雷戈瑞裂谷的一座山脚下，纳特龙湖呈现出火焰燃烧般的亮红色，周围都是不幸落入咸水中的动物遗体。由此可知，许多动物在纳特龙湖无法生存。第二段前两句提到，湖水的腐蚀性非常强，以至于它能灼伤无法适应的动物的皮肤和眼睛，而火烈鸟实际上是唯一生活在这整片死亡之地中的物种，这进一步表明纳特龙湖不适合火烈鸟以外的动物栖息，故答案为A。
2
Flamingos nest only when the lake water is at a specific level so that their babies can .
A.
find safe shelter more easily
B.
grow thick feathers on their feet
C.
stay away from predators
D.
get accustomed to the salty water
本题答案：
A
B
C
D
参考答案：
C
系统解析：
事实细节题。第二段最后两句指出，世界上四分之三的火烈鸟从东非大裂谷的其他盐湖飞过来，在湖水达到特定水位时才出现的盐晶岛上筑巢--如果水位过高，火烈鸟就不能筑巢，如果水位过低，捕食者就会轻快地穿过湖床进行攻击。只有当湖水达到合适的水位时，一条腐蚀性的水沟才能保护幼鸟不 被捕食者伤害。由此可知，火烈鸟只有在湖水达到特定水位时才筑巢，这样它们的幼鸟可以避开捕食者，故答案为C。
3
Flamingos in the Rift Valley are unique in that .
A.
they can move swiftly across lagoons
B.
they can survive well in salty water
C.
they breed naturally in corrosive ditches
D.
they know where and when to nest
本题答案：
A
B
C
D
参考答案：
B
系统解析：
推理判断题。第二段提到，火烈鸟是唯一生活在纳特龙湖的物种。紧接着第三段第一句提到火烈鸟的腿上已经进化出非常坚韧粗糙的皮肤，这样它们就可以耐受盐水。由此可知，东非大裂谷的火烈鸟独特的原因是它们粗糙的腿部皮肤让它们可以在盐水中生存并繁殖，故答案为B。
4
Why can certain species of tilapia sometimes survive around Lake Natron?
A.
They can take refuge in the less salty waters.
B.
They can flee quick enough from predators.
C.
They can move freely from lagoon to lagoon.
D.
They can stand the heat of the spring water.
本题答案：
A
B
C
D
参考答案：
A
系统解析：
事实细节题。第四段第一句提到，也有些鱼，能偶尔成功地在纳特龙湖待上一段时间，因为咸度较低的泻湖是在流入纳特龙湖的温泉外缘形成的。紧接着第二句具体指出三种罗非鱼会有部分时间在那里成长。由此可知，这三种罗非鱼有时能生存在纳特龙湖周围，是因为泻湖的咸度较低，故答案为A。
5
What may be the consequence of Tanzanian government's planned operation?
A.
The accelerated extinction of flamingos.
B.
The change of flamingos' migration route.
C.
The overmining of Lake Natron's soda ash.
D.
The disruption of Lake Natron's ecosystem.
本题答案：
A
B
C
D
参考答案：
D
系统解析：
推理判断题。最后一段第一句指出，这个独特的生态系统可能很快就会面临压力。紧接着第二句说明原因：坦桑尼亚政府再次开采该湖的纯碱，用于制造化学品、玻璃和洗涤剂。第三句则指出尽管规划的工厂将位于40多英里之外，通过管道抽取纯碱，但环保主义者担心它仍会破坏天然的水循环和繁殖地。由此可知，坦桑尼亚政府规划的工厂带来的后果可能是对纳特龙湖生态系统的破坏，故答案为D。
It is the season for some frantic last-minute math—across the country, employees of all stripes are counting backward in an attempt to figure out just how much paid time-off they have left in their reserves. More of them, though, will skip those calculations altogether and just power through the holidays into 2017: More than half of American workers don't use up all of their allotted vacation days each year.
Not so long ago, people would have turned up their noses at that kind of dedication to the job. As marketing professors Silvia Bellezza, Neeru Paharia, and Anat Keinan recently explained in Harvard Business Review (HBR), leisure time was once seen as an indicator of high social status, something attainable only for those at the top. Since the middle of the 20th century, though, things have turned the opposite way—these days, punishing hours at your desk, rather than days off, are seen as the mark of someone important.
In a series of several experiments, the researchers illustrated just how much we've come to admire busyness, or at least the appearance of it. Volunteers read two passages, one about a man who led a life of leisure and another about a man who was over-worked and over-scheduled; when asked to determine which of the two had a higher social status, the majority of the participants said the latter. The same held true for people who used products that implied they were short on time: In one experiment, for example, customers of the grocery-delivery service Peapod were seen as of higher status than people who shopped at grocery stores that were equally expensive; in another, people wearing wireless headphones were considered further up on the social ladder than those wearing regular headphones, even when both were just used to listen to music.
In part, the authors wrote in HBR, this pattern may have to do with the way work itself has changed over the past several decades.
We think that the shift from leisure-as-status to busyness-as-status may be linked to the development of knowledge-intensive economics. In such economies, individuals who possess the human capital characteristics that employers or clients value (e. g. , competence and ambition) are expected to be in high demand and short supply on the job market. Thus, by telling others that we are busy and working all the time, we are implicitly suggesting that we are sought after, which enhances our perceived status.
Even if you feel tempted to sacrifice your own vacation days for fake busyness, though, at least consider leaving your weekends unscheduled. It's for your own good.
6
What do most employees plan to do towards the end of the year?
A.
Go for a vacation.
B.
Keep on working.
C.
Set an objective for next year.
D.
Review the year's achievements.
本题答案：
A
B
C
D
参考答案：
B
系统解析：
推理判断题。第一段第二句指出，他们当中更多的人会干脆不做这些计算，继续在假期奋战，直至迈入2017年：超过半数的美国员工每年都休不完他们的法定假期。由此可知，大多数员工还是会继续工作，故答案为B。
7
How would people view dedication to work in the past?
A.
They would regard it as a matter of course.
B.
They would consider it a must for success.
C.
They would look upon it with contempt.
D.
They would deem it a trick of businessmen.
本题答案：
A
B
C
D
参考答案：
C
系统解析：
事实细节题。第二段第一句指出，不久之前，人们还对这种敬业嗤之以鼻。C项中的look upon it with contempt是定位句中turned up their noses at的同义转述，故答案为C。
8
What did the researchers find through a series of experiments?
A.
The busier one appears, the more respect one earns.
B.
The more one works, the more one feels exploited.
C.
The more knowledge one has, the more competent one will be.
D.
The higher one's status, the more vacation time one will enjoy.
本题答案：
A
B
C
D
参考答案：
A
系统解析：
推理判断题。第三段第一句指出，在一系列实验中，研究人员表明了我们对忙碌，或者至少对其表象，有多么崇拜。紧接着第二句利用实验结果进一步证明了该结论，实验对象认为忙碌的人比悠闲的人社会地位高，也就是说一个人越忙，他的社会地位就越高，人们就越崇拜他，故答案为A。
9
What may account for the change of people's attitude towards being busy?
A.
The fast pace of life in modern society.
B.
The fierce competition in the job market.
C.
The widespread use of computer technology.
D.
The role of knowledge in modern economy.
本题答案：
A
B
C
D
参考答案：
D
系统解析：
事实细节题。第五段第一句指出，我们认为从“闲暇代表社会地位”到“忙碌代表社会地位”的转变，可能与知识密集型经济的发展有关。the shift from leisure-as-status to busyness-as-status表明了人们对忙碌的态度转变，由过去认为闲暇代表社会地位高到如今认为忙碌代表社会地位高，而转变的原因在于知识在社会中所起的作用，故答案为D。
10
What does the author advise us to do at the end of the passage?
A.
Schedule our time properly for efficiency.
B.
Plan our weekends in a meaningful way.
C.
Find time to relax however busy we are.
D.
Avoid appearing busy when we are not.
本题答案：
A
B
C
D
参考答案：
C
系统解析：
推理判断题。定位句指出，即使你很想牺牲自己的假期来假装忙碌，但至少考虑一下把周末空出来不要安排工作，也就是作者建议人们还是要抽空休息一下，故答案为C。
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