Scientists from England’s Newcastle University have discovered that bacteria have the ability to detect smells, according to a study by the university on Sunday.
The team of scientists, led by Dr. Reindert Nijland, discovered that bacteria can detect certain types of smell- producing chemicals, including ammonia (氨) that is produced by other bacteria. Once they sense the smells from other kinds of bacteria, the bacteria will gather together to form a colony (集群) and form a layer of slime (粘液) in order to force the competitors out of their area. The response decreases as the distance between the two bacterial colonies increases.
That slime, also known as biofilm, is one of the primary causes of infection on many medical implants(移植物). Biofilms also slow down ships and are believed to cost the marine industry millions of dollars annually. However, they can also be used to clean up spilled oil floating on the sea, as they grow strong on it.
“This is the first evidence of a bacterial ‘nose’able to detect potential competitors,” Dr. Nijland said in the August 15 statement, which confirms that bacteria possess qualities similar to four of the five senses that humans enjoy (sight, hearing, touch, taste, and smell), the others being touch, taste, and sight.
“The fact that bacteria formed slime when exposed to ammonia has important significance for understanding how biofilms are formed and how we might be able to use them to our advantage,” he added.
Their findings were published in Sunday’s edition of biotechnology journal, and could change the way scientists look at how each of the senses developed over time.
“It was thought for a long time that smell existed only in complex living creatures,” Dr. Nijland said. “Now we see that bacteria are able to do the same, so the indication is that the ability may have developed even earlier.”We learn from the text that biofilms _____.
| A．may cause oil to spill |
| B．can be used to benefit humans |
| C．are the major causes of infection |
| D．are more likely to be found on ships |
Which of the following describes bacteria correctly?
| A．They can talk. |
| B．They cannot see |
| C．They cannot hear. |
| D．They can imitate others. |
The findings may help scientists know more about ______.
| A．how bacteria reproduce |
| B．the development of the senses. |
| C．how to control bacterial infection. |
| D．the complex relation of living creatures |
Which of the following would be the best title for the text?
| A．Bacteria can produce ammonia |
| B．Bacteria have a sense of smell |
| C．Why are biofilms so annoying? |
| D．How do bacteria communicate? |
Three “Great Walls” built around the United States’ Tornado Alley could reduce tornadoes from destroying billions of dollars in property and endangering millions of lives, a physicist has claimed.
Professor Rongjia Tao of Temple University, Philadelphia unveiled a proposal this week calling for the construction of three 1,000-foot barriers up to 100 miles long, which would act like hill ranges and soften winds before tornadoes could form, the BBC reports.
The $16.9 billion plan would call for the faux hill ranges in North Dakota, along the border between Kansas and Oklahoma, and in Texas and Louisiana, ostensibly saving billions of dollars in damage every year, Tao said. The walls would not shelter towns, he said, but instead would soften the streams of hot southern and cold northern air that form tornadoes when they clash in the first place.
But critics laughed at Tao’s proposals. Leading tornado experts pointed to areas that are already protected by hill ranges the size of the barriers Tao is proposing, yet still have plenty of tornados, like parts of Oklahoma, Arkansas and Missouri. And even if the plan did work, it would create more problems than it would solve, scientists said, by creating catastrophic weather side effects.
“Everybody I know is of 100% agreement – this is a poorly conceived idea,” Professor Joshua Wurman of the Center for Severe Weather Research. “From what I can gather his concept of how tornadoes form is fundamentally flawed（有缺陷的）. Meteorologists（气象学家） cringe（尴尬） when they hear about ‘clashing（交锋） hot and cold air’. It’s a lot more complicated than that.”What does the underlined word “unveiled”mean in the fourth paragraph？
| A．reminded | B．came up with | C．referred | D．applied |
What’s the main idea of the passage?
| A．The different opinions on the proposal that the walls will reduce the loss caused by tornadoes. |
| B．How to solve the problems that are caused by tornadoes. |
| C．The proposal mentioned in the paragragh is totally wrong. |
| D．The proposal to reduce tornadoes is effective. |
From the passage, we can infer that__________.
| A．the tornadoes form by clashing（交锋） hot and cold air. |
| B．if the walls are built, they will work well. |
| C．if the plan is carried out, we will have more problems than expected. |
| D．The walls not only soften the winds but also shelter the towns. |
Which of following statements is true according to the passage？
| A．Leading tornado experts think that would soften the streams of hot southern and cold northern air that form tornadoes. |
| B．Professor Joshua Wurman pointed out that the plan will be expensive. |
| C．Professor Rongjia Tao is against the construction of walls to prevent the tornadoes. |
| D．the plan will not be carried out because it will creating serious weather side effects. |
Hawking's Five Easy Steps for Making Yourself a Genius
As we all know，Stephen Hawking writes the book A Brief History of Time that explains the
origin of the universe. The book spent 147 weeks on the New York Times Best Seller List and has
sold 10 million copies. He is，most agree，very smart.
In his recently published autobiography My Brief History，Hawking offers five life lessons on
how to become a genius.
1)Don’t miss opportunities by being too cool
“We showed an air of complete boredom and the feeling that nothing was worth making an
effort for. One result of my illness has been to change all that. When you are faced with the
possibility of an early death, it makes you realize that life is worth living and that there are lots of
things you want to do. ”Seize the moment，as Oxford types would say.
2)Keep it simple
When writing A Brief History of Time，he tried to make science understandable for the rest of
us. “I was sure that nearly everyone is interested in how the universe operates，but most people
cannot follow mathematical equations(数学公式). ”He has trouble with them，too. “This is
partly because it is difficult for me to write them down，but mainly because I don't have an inborn
feeling for equations. My aim in the book was to describe these mental images in words. It is
such an easy book that everybody can understand it.” The moral：You don't have to be a genius to know everything.
3）Have fun
Hawking has a long history of being a joker，and he has placed lots of bets with other
scientists on the nature of black holes. One was with Cal-Tech scientist John Preskill. After
paying off his bet by giving Preskill a baseball encyclopedia，Hawking wrote，“but maybe I should
have just given him the ashes. ”So lighten up! Geniuses like bad jokes too.
4) Always look for a silver lining (even if you are seriously ill)
Hawking's disease has slowly robbed him of the ability to walk，move his arms，even speak.
But，Hawking says，“in some ways I guess my disability has been an assist：I haven't had to
lecture or teach students, and I haven't had to sit in meetings. So I have been able to devote
myself completely to research.”In other words，Hawking was given lemons，and he made
Champagne.
5)Don’t work too hard at school
……The passage tells us the facts about A Brief History of Time EXCEPT that ________.
| A．it included Hawking's five life lessons on how to become a genius |
| B．it has sold 10 million copies up to now |
| C．it spent 147 weeks on the New York Times Best Seller List |
| D．it explained the origin of the universe |
According to the passage，which of the following statements is guiding you to be a genius?
| A．Place lots of bets with your friends. |
| B．Find something good even in bad situations. |
| C．Seize the moment to learn everything. |
| D．Get to know everything including math equations. |
Hawking shows his viewpoint by ____________.
| A．making comparisons | B．quoting a famous saying |
| C．talking about his own experience | D．listing the numbers and equations |
BEIJING, March 7 (Xinhua) -- Beijing will take a series of measures to tackle its environmental problems and is confident they will not derail its bid to host the 2022 Winter Olympics, an official said on Thursday.
Beijing has formulated 84 measures to deal with environmental issue and air pollution, said Li Shixiang, Beijing's executive vice mayor, at the ongoing annual session of the National People's Congress, the top legislature.
Beijing is expected to cut its current coal consumption by more than half to 10 million tonnes a year by 2017. It will also impose tough controls over industrial pollution and dust fall from construction sites, while reducing the number of newly added vehicles every year to 150,000, said Li.
He said the Chinese capital will benefit from the experience of successfully holding the 2008 Beijing Olympics.
Beijing and Zhangjiakou City in neighboring Hebei Province will launch a joint bid to host the 2022 Winter Olympic Games, the Chinese Olympic Committee (COC) announced in early November 2013.
Beijing will bid to stage the ice events while Zhangjiakou will seek hosting rights for snow sports, according to the COC.
Beijing has been plagued by choking smog and it is a great concern for its chances of hosting the Winter Olympics. What does the underlined word “plagued”mean in the last paragraph？
| A．annoyed | B．destroyed | C．striked | D．broken |
Which statement is true according to the passage？
| A．Beijing will cut its current coal consumption. |
| B．Beijing will reduce the number of newly added vehicles every year. |
| C．Beijing will firmly control industrial pollution and dust fall from construction sites. |
| D．Smog will hurt Beijing's Winter Olympics bid. |
A report consistently brought back by visitors to the US is how friendly，courteous and helpful most Americans were to them．To be fair，this observation is also frequently made of Canada and Canadians，and should best be considered North American．There are，of course，exceptions．Small-minded officials，rude waiters，and ill-mannered taxi drivers are hardly unknown in the US．Yet it is an observation made so frequently that it deserves comment．For a long period of time and in many parts of the country, a traveler was a welcome break in an otherwise dull existence．
Dullness and loneliness were common problems of the families who generally lived distant from one another．Strangers and travelers were welcome sources of diversion，and brought news of the outside world．The harsh realities of the frontier also shaped this tradition of hospitality．
Someone traveling alone，if hungry，injured，or ill，often had nowhere to turn except to the nearest cabin or settlement．It was not a matter of choice for the traveler or merely a charitable impulse on the part of the settlers．It reflected the harshness of daily life： if you didn‘t take in the stranger and take care of him，there was no one else who would．And someday，remember，you might be in the same situation．Today there are many charitable organizations which specialize in helping the weary traveler．Yet，the old tradition of hospitality to strangers is still very strong in the US，especially in the smaller cities and towns away from the busy tourist trails．“I was just traveling through，got talking with this American，and pretty soon he invited me home for dinner—amazing．” Such observations reported by visitors to the US are not uncommon，but are not always understood properly．
In the eyes of visitors from the outside world，___________．
| A．rude taxi drivers are rarely seen in the US |
| B．small-minded officials deserve a serious comment |
| C．Canadians are not so friendly as their neighbors |
| D．most Americans are ready to offer help |
It could be inferred from the last paragraph that ___________．
| A．culture exercises an influence over social interrelationship |
| B．courteous convention and individual interest are interrelated |
| C．various virtues manifest themselves exclusively among friends |
| D．social interrelationships equal the complex set of cultural conventions |
Families in frontier settlements used to entertain strangers ___________．
| A．to improve their hard life |
| B．in view of their long-distance travel |
| C．to add some flavor to their own daily life |
| D．out of a charitable impulse |
The tradition of hospitality to strangers ___________．
| A．tends to be superficial and artificial |
| B．is generally well kept up in the united States |
| C．is always understood properly |
| D．has something to do with the busy tourist trails |
What’s the author’s attitudes toward the American‘s friendliness？
| A．Favorable． | B．Unfavorable． |
| C．Indifferent． | D．Neutral． |
Every year holidays Broughton teams up with Sopraviva Trekking to offer twelve days of unforgettable adventure in a tropical rain forest．Depending on where this year’s rain forest adventure is located, you may be going to Borneo, Malaysia ,Indonesia,or even to the greatest rain forest of them all, the mighty Amazonian forest．
You will fly with your fellow adventurers to one of our special base camps at the edge of the forest, where you will be given five days of survival training ,and talks on the local wildlife by trained and experienced experts．You will also go on walks which take you deeper and deeper under the forest canopy until on your final night you camp out in the rain forest itself．
Then you transfer by bus into the forest itself．If you go on one of the Asian holidays, you will have to walk the final miles to the camp site itself, to avoid disturbing the local ecology．All of the Sopraviva sites have been carefully built to conform with the latest regulations, and to cause the minimal amount of disturbance to the local wildlife．
From the camp ,you will go on daily walking tours to experience for yourself the beauty and diversity of the forests, and plants and vegetation that can be found nowhere else on the planet．Remember that these adventure holidays take you deep into the wilderness ,and they are not suitable for families with young children or for anyone who is not physically able to meet the demands of this kind of adventure．Also remember that in order to preserve the delicate ecological system that you will be walking through ,no more than two dozen guests can stay at any camp at one time, so if you want to go on one of these very special holidays ,you will need to book early!If you want to go on the camp ,you will first have to ．
| A．attend talks on the local wildlife |
| B．have survival training |
| C．walk the final five miles |
| D．book beforehand |
What does the organizer of the camp mainly stress?
| A．Disturbing the local ecology． |
| B．Preserving the forest environment． |
| C．Private possessions and possible dangers． |
| D．The survival training |
Go on daily walking tours and you’ll enjoy ．
| A．the wilderness | B．the Amazonian forest |
| C．the Asian forest | D．the forest canopy |
Which of the following people is/are allowed to enter the forest?
| A．A family with young kids． |
| B．A person with physical problems． |
| C．Walking tourists． |
| D．Cyclists． |
Which of the following is true of the holiday camp?
| A．It is free of charge |
| B．It lasts 12 days． |
| C．It is organized by Broughton． |
| D．It attaches little importance to ecology． |
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