There are certain areas on Mars where we don’t dare tread. NASA forbids spacecraft from visiting spots that possibly host liquid water, and so where life might be able to thrive, for fear of contaminating (感染) Mars with Earth microbes. But an analysis of the salty liquids on Mars suggests we needn’t worry, because life as we know it should be unable to exist anywhere on the planet’s surface.
Edgard Rivera-Valentin at the Lunar and Planetary Institutein Texas and his colleagues used readings of the temperature and relative humidity across Mars to map the presence of salty water. Any water on the surface is likely to be salty, simply because the surface is. This boosts the chances of water being liquid because salt lowers its freezing point.
It is like when you throw salt on an icy sidewalk, says Danielle Nuding at NASA’s Jet Propulsion Laboratory in California. “It’s the same chemistry happening.”
Unfortunately, the saltier the water, the less likely anything can survive in it. The team found that even though there could be briny (盐分多的) water on the surface of Mars up to 18 per cent of the year, depending on the season, no microbe we have ever seen on Earth would be able to reproduce there.
Life as we know it is not going to find these brines and survive because it’s either going to be way too cold or way too salty,” says Rivera-Valentin, who presented the results at the Lunar and Planetary Science Conference in Texas.
That doesn’t mean we can’t contaminate Mars: brines with different types of salts mixed together might be friendlier to life and temperatures just below the surface are much less extreme. Nevertheless, as long as we don’t dig down, it might be highly unlikely or even impossible for rovers (飞行器) such as Curiosity to contaminate Mars.
“The level of sterilization (杀菌) that we’ve done with Curiosity should be good enough to ignore the ban on visiting what we’ve been calling special regions until now, says Jennifer Hanley at Lowell Observatory in Arizona. I think that we’re OK to go. Visiting these regions would be particularly helpful because, while they are in theory the most vulnerable areas on Mars, they are also the most interesting.
For example, arguments have been raging for over a decade about whether dark streaks on Martian slopes called recurring slope lineae are flowing water or just dust. A quick visit by Curiosity, which is near an area where the flows often form, could solve it once and for all.
Even if areas with water are inhospitable to Earth life, they could still be home to native Martian life forms.
“If you had life that originated on Mars when it was more habitable, it could be that as Mars changed, life could have gradually adapted to the new, more extreme conditions,” says Rivera-Valentin.
1.NASA forbids spacecraft from visiting the special regions on Mars because .
A.life is unable to thrive there, thus there’s no point of visiting them
B.Martian life probably exists there and might threaten human beings
C.they worry Earth microbes might survive there, thus contaminating Mars
D.human beings know nothing about these areas and they are dangerous to us
2.Which of the following statements is true?
A.Mars surface being salty provides evidence that Mars hosts liquid water.
B.Earth life is unlikely to contaminate Mars because the surface of the planet is either too cold or too salty.
C.The fear of contaminating Mars is unnecessary because human beings won’t contaminate Mars under any circumstances.
D.Jennifer Hanley thinks human beings should explore the special regions on Mars in order to confirm the existence of Martian life.
3.What is the point of visiting the special regions on Mars?
A.Martian life might be found.
B.Liquid water might be found.
C.Many puzzles about Mars could soon be solved.
D.No humans have ever visited those regions before.
4.In the passage, you can find the answers to all the questions except .
A.whether the surface of Mars is salty or not
B.whether any native Martian life forms exist
C.whether Earth life is able to survive on Mars or not
D.whether the rover Curiosity will contaminate Mars
The great recession may be over,but this era of high joblessness is probably beginning.Before it ends,it will likely change the life course and character of a generation of young adults.And eventually,it is likely to reshape our politics,our culture,and the character of our society for years.
No one tries harder than the jobless to find silver linings in this national economic disaster. Many said that unemployment, while extremely painful, had improved them in some ways: they had become less materialistic and more financially prudent(节俭的); they were more aware of the struggles of others. In limited respects, perhaps the recession will leave society better off. At the very least, it has awoken us from our national fever dream of easy riches and bigger houses, and put a necessary end to an era of reckless(鲁莽的) personal spending.
But for the most part,these benefits seem thin,uncertain,and far off.In The Moral Consequences of Economic Growth,the economic historian Benjamin Friedman argues that both inside and outside the U.S.,lengthy periods of economic stagnation or decline have almost always left society more mean-spirited and less inclusive,and have usually stopped or reversed the advance of rights and freedoms.Anti-immigrant sentiment typically increases,as does conflict between races and classes.
Income inequality usually falls during a recession, but it has not shrunk in this one. Indeed,this period of economic weakness may reinforce class divides, and decrease opportunities to cross them-especially for young people. The research of Till Von Wachter, the economic at Columbia University, suggests that not all people graduating into a recession see their life chances dimmed: those with degrees from elite(精英) universities catch up fairly quickly to where they otherwise would have been if they had graduated in better times;it is the masses beneath them that are left behind.
In the Internet age, it is particularly easy to see the resentment that has always been hidden within American society. More difficult, in the moment, is discerning precisely how these lean times are affecting society's character. In many respects, the U.S. was more socially tolerant entering this recession than at any time in its history, and a variety of national polls on social conflict since then have shown mixed results. We will have to wait and see exactly how these hard times will reshape our social fabric(组织). But they certainly will reshape it,and all the more so the longer they extend.
1.By saying "to find silver linings" (Para.2) the author suggests that the jobless try to_____.
A.seek help from the government
B.explore reasons for the unemployment
C.make profits from the troubled economy
D.look on the bright side of the recession
2.Benjamin Friedman believes that economic recessions may_
A.impose a heavy burden on immigrants
B.bring out more evils of human nature
C.promote the advance of rights and freedoms
D.ease conflicts between races and classes
3.The research of Till Von Wachter suggests that in the recession graduates from elite universities tend to ____
A.lag behind the others due to decreased opportunities
B.catch up quickly with experienced employees
C.see their life chances as dimmed as the others
D.recover more quickly than the others
4.The author thinks that the influence of hard times on society is____
A.certain B.positive
C.unimportant D.destructive
Recent data released from the Department of Labor in the US show that for the first time in 10 years, women make up more than half (50.04%)of the workforce. Many have celebrated this milestone as proof that women are inching toward equality in the workplace. After all, a symbol of women's equality in America has always been increased via labor force participation.
For women in today's economy, however, increased employment also carries an increased burden. Women earn less, have less flexibility in terms of their work schedules to meet caretaking demands, and are more likely to experience discrimination based on gender or sexual harassment than their male counterparts in the workforce.
Women earn less than men in nearly every occupation for which there is available data. If we do nothing, women will not reach economic equality with men until 2059.For women of color, it will take more than a century:2130 for black women and 2224 for Hispanic women(those from Latin America).This means women will have to work longer or hold multiple jobs to make ends meet and to care for their families.
Increased employment among women has not translated into less work at home. Many women in the workforce are still primarily responsible for the lion's share of housework and caretaking responsibilities compared with men.
A new study by Oxfam America-Institute for Women's Policy Research finds that women in the United States spend 37%more time on household and care work than their male counterparts, limiting career choices and economic mobility, and affecting their overall health and well-being. Black and Hispanic women spend nearly twice as much time on unpaid housework and caretaking demands as their male counterparts.
Much has been made about our strong economy as measured by how well the stock market performs and low unemployment. There's no doubt the increase in workforce participation among women will help boost this narrative. However, it does not mean that women are more economically secure.
In today's economy, working and middle-class families continue to struggle with rising housing and health care costs, stagnant wages and a shift to a technology-driven economy fueled by automation and the loss of manufacturing jobs. These trends have an extreme impact on women.
1.Why have people celebrated women's taking up more than half of the workforce?
A.Because women are likely to replace men in some fields.
B.Because that is the symbol of labor force participation.
C.Because it indicates more equality for women at workplace.
D.Because the data was released from the Department of Labor.
2.The numbers in Para.3 are used to emphasize that
A.women's inequality is a hard nut to crack. B.women have to bear an increased burden.
C.women earn less than men in every occupation. D.women of color see no hope to reach equality.
3.Why doesn't women's employment mean women are more economically secure?
A.Manufacturing jobs are increased by high-tech automation.
B.The trends in today's economy are unfavourable to women.
C.Economy is measured by the performance of the stock market.
D.Women are responsible for rising housing and health care costs.
4.Which would be the best title for this passage?
A.Women's Participation and Economic growth.
B.Over Half of Women Have Entered the Workforce.
C.Women Spend More Time on Household Than Men.
D.Women's Increased Employment Carries Increased Burden.
We’ve certainly seen a dog nursing a wound, or a deer calling out in pain. But many animals suffer in silence. The most silent sufferers in the animal world may be fish.
Do fish feel pain? A new study from the University of Liverpool has found that fish feel pain in a way that’s “strikingly similar” to humans. For the study, Lynne Sneddon, from the university’s Institute of Integrative Biology, reviewed the existing body of research-98 studies in all-and concluded that they feel pain just as sharply as we do.
“When subject to a potentially painful event, fish show changes in behavior such as stopping feeding and reduced activity, which are prevented when a pain-relieving drug is provided. In fact, like us, they breathe heavily and stop eating when they’re hurting. They will even rub the part of their body that aches.” Sneddon notes in a university release.
To understand pain in other species, scientists look at nociceptors, which send signals to the brain when the body is being damaged. Humans have them throughout their skin, bones and muscles. Nociceptors have also been found in many other species, including even those tiny fruit flies. Fish have the same means to detect pain signals and the equipment to receive them.
Besides, the fishermen’s opinion that fish feel no pain just doesn’t add up from an evolutionary view. Pain is an efficient messenger that tells us that we’ve got a problem. An animal that can’t feel it won’t get that memo(备忘录), even if it hurts itself.
“If we accept fish experience pain, then this has great significance for how we treat them,” Sneddon says. “Care should be taken when handling fish to avoid damaging their sensitive skin and they should be humanely caught and killed.”
1.What will a fish do when its lips get hurt?
A.It might rub its lips. B.It will keep its mouth open.
C.It will swim around like crazy. D.It will keep eating to forget pain.
2.What is the significance of the study according to Sneddon?
A.People will treat fish in a kinder way.
B.People can understand evolution better.
C.People can develop more drugs to save fish.
D.People will think of more ways to catch fish.
3.What does the underlined part “add up” probably mean?
A.disappear B.put forward C.make sense D.happen
假定你是李华，最近，你校成功举办了以“最美中国文化”为主题的文艺表演活动。请给你的英国朋友David写一封邮件，内容包括：
1. 活动的时间、地点、参加者；
2. 表演的节目；
3. 参加活动的感受。
注意：
1. 词数100左右；
2. 可以适当增加细节，以使行文连贯。
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假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。
增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。
删除：把多余的词用斜线（\）划掉。
修改：在错的词下划一横线，并在该词下面写出修改后的词。
注意：1. 每处错误及其修改均仅限一词；
2. 只允许修改10处，多者（从第11处起）不计分。
When I finished all of my exam, my family drove to the countryside for a holiday. On our way, my favorite scarf flew out of the window suddenly and is gone. I felt very sad, regretting that when I hadn’t kept the scarf well. Soon after, we stopped at a service station. Feel upset, I found a bench and was about to ate my sandwich when a motorcyclist pulled into the station, “Is that your blue car?” he asked me. Although I felt surprising, I nodded quickly. A man pulled out the very scarf from my backpack and handed it to me. He then returned his motorcycle and wanted to leave. I went up and repaid him thankful by giving him a hug.
