Four species of bacteria – three of them previously unknown to science – have been discovered on board the International Space Station (ISS), starting questions about how they got there, and how they have managed to survive.
Their discovery may also improve future efforts to cultivate crops during long spaceflight missions, since related species are known to promote the growth of plants and help them fight off pathogens（病原菌）.
Previous studies had suggested that certain bacteria could survive the hard conditions of space, which survived on the space station’s surface for three years. They were deliberately placed there to test the theory that life exists throughout the universe and may be transported between planets by space dust, asteroids（小行星）,or even polluted spacecraft.
The new bacteria were similarly identified from swabs（棉签）of various locations inside the ISS. One was discovered on a dining table; another on an overhead board in a research area used to study low gravity; the third in the Cupola observatory. The fourth species, which was already known of, was found on an old air-purifying filter（净化过滤器）, which had been returned to Earth. All of them are rod-shaped bacteria belonging to the family – usually found in soil and fresh water, where they help to promote plant growth and defend against harmful bacteria.
They’re most likely to have been transferred to the ISS from Earth – rather than coming from outer space – and have either survived since the the beginning of the station, or were introduced when new astronauts or supplies arrived.
It is important to understand the types of microbes（微生物）that can accumulate, survive, and even grow well in this unique environment, because they may affect the health of crew, the spacecraft’s structure, or dirty the planets and astronomical bodies they visit.
1. Why was the discovery of the bacteria important?| A．They are all well known species. | B．They are all previously unknown. |
| C．They are good for people’s health. | D．They are helpful with space planting. |
| A．They can not live in hard conditions. | B．They can be transported by space dust. |
| C．Some kinds have a very strong life. | D．Some kinds exist throughout the universe. |
| A．They may strengthen the spacecraft. | B．They are unlikely to come from Mars. |
| C．They will not put other planets to danger. | D．They can hardly grow in the spacecraft. |
相似题推荐
【推荐1】We are naturally drawn to friends and colleagues with familiar voices, scientists have found. People prefer those who have a similar accent, intonation and tone of voice to themselves, they discovered.
Previous research has focused on how a male or female voice sounds. Men with deeper voices and women with slightly higher voices were thought to sound more attractive, because they suggest a bigger or a smaller body.
But the new study, published by a linguistics expert in Canada, suggests there is a more complex mechanism(机制)at play. Dr Molly Babel, from the University of British Columbia in Canada, said, “The voice is an amazingly flexible tool that we use to construct our identity. Very few things in our voices are changeless, so we felt that our preferences had to be about more than a person’ s shape and size.’’
She recorded 30 volunteers’ voices and asked each to rate the others’ attractiveness on a scale of one to nine. Each participant was from western America, with similar accents. The people we assessed were all in the same dialect group, but they showed that dialect to different degrees.
“We seem to like people who sound like we sound, we like people who fit within what we know, ” Dr Babel said. She also found that breathy voices in women-typified by the famous American actress Marilyn Monroe-were seen as more attractive.
The breathy tone, caused by younger and thinner vocal cords(声带), implied youthfulness and health. A creaky (咯吱作响的)voice, suggesting a person has a cold, is tired or smokes, was seen as unattractive. The participants preferred men who spoke with a shorter average word length and deeper voices.
1. The main purpose of the text is to ___________.| A．inform readers of the new findings of voices | B．compare male voices with female voices |
| C．argue against women’s voices of speaking | D．encourage men to use deeper voices to speak |
| A．introduce a creaky voice | B．explain a breathy voice |
| C．challenge previous research | D．promote her reputation |
| A．body size and shape | B．shorter word length |
| C．thicker vocal cords | D．the same social groups |
| A．A young lady with a thin voice | B．An old lady with a silvery voice |
| C．A deep-voiced man with a dry throat | D．A little man with a quiet and gentle voice |
【推荐2】Here are a few signs you can look for to see if you and your pet have love for each other.
Lying onto its back
Your cat's stomach is a very weak place. If it lies onto its back and shows its stomach, it's telling you it's comfortable around you. This doesn't necessarily mean it wants you to touch its stomach. It's mainly a sign that it feels protected when you're near since being on its back is a powerless position.
Eating out of your hand
Usually, cats won't take food from a human's hand unless it is someone they trust very much. Cats are instinctively careful, so they don't take treats easily from strangers' hands, unlike many dogs. If you can feed them snacks or food from your hand, it's a sure sign that they trust you.
Bringing you gifts
Even if you don't have a cat, you've probably heard about cats bringing their owners little "presents" in the form of dead animals. However, while you might view them as "presents" only sarcastically (讽刺地), your cat doesn't! For them, their prey stands for victory, and their instinctual nature as wild hunters. Wild cats would catch food for their young, so your cat's "gift" of its latest catch just means it considers you family.
Giving you a "thumbs up" with its tail
Cats can send all sorts of different messages just with their tails. A cat's tail is a good barometer(晴雨表) of their mood. One simple way to know if your cat trusts you is to see if its tail stands straight up, especially when it sees you or walks toward you. Some cat experts consider it to be a sign of praising in cat language.
1. What do "Lying onto its back" and "Eating out of your hand" show in common?| A．The cat wants to relax. | B．The cat feels safe. |
| C．The cat is grateful to you. | D．The cat hopes to reward you. |
| A．It wants to pay you back. | B．It is just showing off its ability. |
| C．It regards you as a family member. | D．It is giving a thank-you sign. |
| A．Praising you. | B．Laughing at you. |
| C．Forecasting weather. | D．Warning you. |
【推荐3】The Heat Vacuum (真空)
Air-conditioning accounts for nearly 15 percent of building energy use in the U.S. today. The number of days with record heat could increase in the coming decades. These two facts present a difficult problem:
Researchers at Stanford University say part of the solution is a material that pulls heat from buildings and radiates it into outer space.
Shanhui Fan, senior author of a 2014 Nature paper describing the work, imagines such mirrors covering the roofs of buildings. With its roof continually releasing heat, a building’s air-conditioning can relax and consume less energy.
| A．In a warming world, how can we cool our homes and workplaces while reducing energy use? |
| B．The researchers spent the first five years studying reflection. |
| C．What is the most economical and feasible way to save energy for our future generations? |
| D．There could be other applications. |
| E．To solve the problem, the Stanford team created what amounts to a very effective mirror. |
| F．The basic concept is known as radiative cooling. |
【推荐1】Listening test is one of the most important parts of the English exam. Here are some tips for you.
Before you start to listen, you need to relax. Don't be stressed out. And try to read the questions. These questions usually help you understand the conversation or the passage.
Then listen carefully to the first sentence. It usually tells you the main idea of the passage. When you're listening, try to do some thinking and take some notes, such as: What happened? When, where, and how? What does the speaker want to tell us? In this way, you may understand the passage better.
Please remember not to think about one or two words for a long time.When you hear some words you don't know, don't spend too much time on them. Very often, you'll find out what they mean later when you go on with the listening.
1. This passage mainly talks about some________.| A．tips on listening | B．tips on speaking |
| C．tips on reading | D．tips on writing |
| A．excited | B．relaxed |
| C．stressed out | D．worried |
| A．the answers to the questions | B．where to write the answers |
| C．the main idea of the passage | D．how much time left for the listening test |
| A．remember every word | B．take some notes |
| C．understand all the words | D．think about one or two words for a long time |
| A．questions | B．first sentence | C．notes | D．A, B and C |
【推荐2】If you followed the Rio Olympic Games, you may have noticed that several athletes, including US swimmer Michael Phelps, had circular bruises (青肿) on their bodies. These bruises were the result of “cupping (拔火罐) therapy”, a traditional Chinese medicinal practice that has been around for more than 2,000 years.
Many athletes say that they have benefited from the therapy. Phelps used the therapy in the fall of 201 and has used it about twice a week since, reported ABC News. Another US swimmer, Dana Vollmer, also believes that “it really helps with blood flow”.
However, some have said that the supposed health effects result from people’s feeling that the treatment works, rather than any physical effect of the treatment. To figure out cupping therapy has any physical effect, last year researchers from Germany carried out a test in which a false treatment was provided.
In the study, the same type of cups was used in the real treatment and the false treatment. But in the false treatment, the cups had a hole at the top so that they couldn’t create the proper suction (吸力).
The tested patients, who suffered from a disorder that caused a lot of pain, were told that they would receive either a traditional cupping or “soft cupping”. But they were not informed that the so-called “soft cupping” was a false treatment.
It turned out that most patients correctly guessed which kind of cupping they had received. In both groups, patients also experienced about the same reductions in pain. “The results suggest the effects of cupping therapy might come from factors that are not necessarily part of the treatment itself,” the researchers told the Live Science website.
The question of whether cupping therapy works still needs to be answered. “But because the treatment is relatively safe and it could be helpful for some people, the therapy can be used as part of a comprehensive treatment program involving other exercises, nutritional choices and lifestyle changing,” Dr Brent Bauer, director of the US Complementary and Integrative Medicine Program at Mayo Clinic, told Live Science.
1. Why does the author mention Michael Phelps in Paragraph 1?| A．To give athletes a new way to swim faster. |
| B．To provide athletes with a new way of treatment. |
| C．To introduce the topic on cupping therapy. |
| D．To show swimmers suffer from disorders. |
| A．promote the health effects of cupping therapy |
| B．see whether cupping therapy has a physical effect |
| C．compare traditional cupping with the soft cupping |
| D．compare cupping therapy’s effects on different groups of people |
| A．Different people need different types of cupping therapy. |
| B．The real treatment and false treatment almost have the same effects. |
| C．The results show that cupping therapy is surely not part of the treatment. |
| D．Cupping therapy is only effective when used with lifestyle changing. |
| A．is a fast and easy treatment for people to carry out |
| B．is a newly invented way to cure some diseases |
| C．needs a long period of time to take effect |
| D．can be used together with other treatments |
【推荐3】New research led by scientists at the University of Massachusetts Amherst has revealed that the spiny pollen (带刺花粉) of plants in the sunflower family can reduce infection of a common bee parasite (寄生生物) by up to 94 percent. The sunflowers'spiny pollen can destroy a parasite called C. bombi (熊蜂短膜虫), which has been significantly reducing bumblebee populations.
To investigate how sunflowers help bumblebees resist C. bombi, the researchers separated the spiny outer shell of the pollen from the chemical metabolites (代谢物) in the pollen’s core. They then mixed the spiny pollen shells of sunflowers, with the chemistry removed, into the pollen fed to one group of bees.
Another group was fed wildflower pollen with sunflower metabolites and no sunflower shells. The researchers discovered that the bees that ate the spiny sunflower pollen shells had the same response as bees feeding on whole sunflower pollen. These bees had a markedly reduced risk of C. bombi infection compared to those fed sunflower metabolites.
Bumblebees, which are vital pollinators of crops and wildflowers, are experiencing a rapid decline in their populations worldwide. Habitat loss due to urbanization and agricultural intensification is the greatest threat to bumblebees. Climate change is also taking a toll on bumblebees. As temperatures rise, bumblebees are forced to move further north to cooler climates, which can affect their ability to find food and nesting sites. Pesticide use is another significant threat to bumblebees. These chemicals are harmful to them and can damage their navigation and immune systems, leading to reduced reproductive success. Bumblebees play a vital role in maintaining healthy and diverse ecosystems. Understanding how sunflowers protect bees from disease could help us identify other flowers that have similar protective properties. Through this, researchers can work towards developing new strategies to help conserve bumblebees.
1. How does the spiny pollen of sunflowers benefit bees?| A．It protects them from predators. | B．It improves their sense of smell. |
| C．It can be used for their nest building. | D．It helps them resist parasite infections. |
| A．By collecting data. | B．By making comparisons. |
| C．By referring to previous studies. | D．By surveying experienced farmers. |
| A．Habitat loss. | B．Climate change. | C．The use of pesticides. | D．Environmental pollution. |
| A．It offers a way to increase sunflower yield. |
| B．It draws public attention to the role of ecosystems. |
| C．It provides a new idea for protecting bumblebees. |
| D．It allows people to distinguish between different plants species. |
