Dogs greet other dogs nose-first, as it were—sniffing each other from fore to (especially) aft. People are not quite so open about the process of sniffing each other out. But the size of the perfume industry suggests scent is important in human relations, too. There is also evidence that human beings can infer kinship (亲戚关系), deduce emotional states and even detect disease via the sense of smell.
Now, researchers of the Weizmann Institute of Science in Israel, have gone a step further. They think they have shown, admittedly in a fairly small sample of individuals, that friends actually smell alike. They have also shown that this is probably the case from the beginning, with people picking friends at least partly on the basis of body odour (气味), rather than the body odours of people who become friends subsequently converging (趋同).
They stated their research by testing the odours of 20 pairs of established non-romantic, same-sex friends. They did this using an electronic nose and also two groups of specially employed human “smellers.” The e-nose employed a set of gas sensors to assess T-shirts worn by participants. One group of human smellers were given pairs of these shirts and asked to rate how similar they smelt. Those in the other group were asked to rate the odours of individual T-shirts on five subjective dimensions: pleasantness, intensity, attractiveness, competence and warmth. All three approaches yielded the same result. The T-shirts of friends smelt more similar to each other than the T-shirts of strangers. Friends, in other words, do indeed smell alike.
Why scent might play a role in forming friendships remains obscure. Other qualities related with being friends, including age, appearance, education, religion and race, are either immediately obvious or rapidly become so. But while some individuals have strong and noticeable body odour, many—at least since the use of soap has become widespread—do not. It is present. But it is subconscious.
1. Why are dogs and the perfume industry mentioned in Paragraph 1?| A．To list some examples. | B．To introduce the topic. |
| C．To make a comparison. | D．To provide relevant evidence. |
| A．The body odour is the beginning of friendship. |
| B．People start to smell alike after becoming friends. |
| C．Many people are involved as the research samples. |
| D．Odour-matching may be a reason for being friends. |
| A．By trying to yield the same result with three approaches. |
| B．By testing the odours of 20 non-romantic friends of the same sex. |
| C．By asking each group to rate the odours of T-shirts on five dimensions. |
| D．By employing e-nose and human smellers to assess the odours of T-shirts. |
| A．Unclear. | B．Important. | C．Obvious. | D．Subjective. |
相似题推荐
【推荐1】With a brain the size of a pinhead, insects perform fantastic navigational (导航的) abilities. They avoid obstacles and move through small openings. How do they do this, with their limited brain power? Understanding the inner workings of an insect’s brain can help us in our search towards energy-efficient computing, physicist Elisabetta Chicca of the University of Groningen demonstrates with her most recent result: A robot that acts like an insect.
In search of the neural (神经的) mechanism that drives insect behaviour, PhD student Thorben Schoepe developed a model of its neuronal activity and a small robot that uses this model to navigate. Schoepe’s model is based on one main principle: always steer towards the area with the least apparent motion.
He had his robot drive through a long “corridor”— consisting of two walls with a random print on it—and the robot centred in the middle of the corridor, as insects tend to do. In other virtual environments, such as a space with obstacles or small openings, Schoepe’s model also showed similar behaviour to insects.
“The model is so good,” Chicca concludes, “that once you set it up, it will perform in all kinds of environments. That’s the beauty of this result.”
The fact that a robot can navigate in a realistic environment is not new. Rather, the model gives insight into how insects do the job, and how they manage to do things so efficiently.
Chicca explains, “Much of robotics is not concerned with efficiency. We humans tend to learn new tasks as we grow up and within robotics. This is reflected in the current trend of machine learning. But insects are able to fly immediately from birth. An efficient way of doing that is hardwired in their brains. In a similar way, you could make computers more efficient.”
1. Why does Chicca want to study how the insect brain works?| A．To make computers more efficient. | B．To make use of insects’ brain power. |
| C．To understand the habit of insects. | D．To reveal the inner part of insects’ brain. |
| A．Stretch. | B．Stare. | C．Drive. | D．Work. |
| A．Regretful. | B．Shocked. | C．Confused. | D．Satisfied. |
| A．How to make a robot that acts like an insect. |
| B．Why insects navigate more efficiently than robots. |
| C．Why a robot can navigate in a realistic environment. |
| D．How humans tend to learn new tasks as they grow up. |
【推荐2】When we think of animals and plants, we have a pretty good way of dividing them into two distinct groups: one turns sunlight into energy and the other has to eat food to make its energy. Well, those dividing lines come crashing down with the discovery of a sea slug（海蛞蝓）that is truly half animal and half plant. It’s pretty unbelievable how it has managed to steal the genes of the algae（海藻）on which it feeds.
The slugs can use the stolen genes to produce chlorophyll（叶绿素）, which gets energy from sunlight, and hold these genes within their bodies. And so far, this green sea slug is the only known animal that can be truly considered solar-powered. Many scientists have studied the green sea slugs to confirm that they are actually able to create energy from sunlight.
In fact, the slugs use the genetic material so well and they pass it on to their further generations. The babies keep the ability to produce their own chlorophyll, though they can’t produce energy from sunlight until they’ve eaten enough algae to steal the necessary genes.
“There is no way on earth that genes from algae should work inside animal cells,” says Sidney Pierce from the University of South Florida. “And yet here, they do. They allow the animal to rely on sunshine for its nutrition. So if something happens to their food source, they have a way of not starving to death until they find more algae to eat.”
The sea slugs are so good at gathering energy from the sun that they can live up to 9 months without having to eat any food. They get all their nutritional needs met by the stolen genes.
1. What enables the sea slug to live like a plant?| A．The genes it gets from the sea plant algae. | B．The nutrients it obtains from other animals. |
| C．The energy it steals from the sea plant algae. | D．The chlorophyll it receives from its ancestors. |
| A．It looks like both a plant and an animal. |
| B．It gets energy from both food and sunlight. |
| C．It can produce energy on its own since birth. |
| D．It cannot pass the stolen genes to its baby slugs. |
| A．They are stolen from animals like the sea slug. |
| B．They can’t function unless exposed to sunlight. |
| C．They don’t usually function inside animal cells. |
| D．They can readily be transformed to sea slug genes. |
【推荐3】Plant-eating dinosaurs probably arrived in the northern half of the world millions of years after meat-eating dinosaurs, a recent study found. Their late arrival was likely a result of climate changes that took place hundreds of millions of years ago.
The study used a new way to ascertain the age of dinosaur remains found in Greenland. Researchers found that the plant-eating dinosaurs were about 215 million years old. The mineralized（石化的）remains of bones are called fossils. Earlier, those fossils were thought to be as old as 228 million years. The findings could change how scientists think about dinosaur movements, or migrations.
The earliest dinosaurs all seemed to first develop about 230 million years ago or longer. They appeared in what is now South America. Then, the creatures moved north and spread all over the world. The new study suggests not all dinosaurs moved at the same time.
So far, scientists have not found any evidence of plant-eating dinosaurs living in the Northern Hemisphere before 215 million years ago. One of the best examples of these is the Plateosaurus, a two-legged, 7-meter-long plant-eater that weighed around 4,000 kilograms. However, meat. eaters lived worldwide by at least 220 million years ago.
During the Triassic（三叠纪）period, 230 million years ago, CO2 levels were 10 times higher than now. The Earth was hotter with no ice sheets at the poles and two areas of extreme deserts north and south of the equator（赤道）. It was so dry in those areas that there were not enough plants for the plant-eaters to survive. But there were enough insects so that meat-eaters could.
About 215 million years ago, CO2 levels dropped. The drop resulted in more plant life in the deserts. The plant-eaters were then able to make the trip. Triassic changes in CO2 levels were from volcanoes and other natural forces. The changes were different from those in our times, when the burning of coal, oil and natural gas are considered the main causes of climate change.
1. Which can best replace the underlined word "ascertain" in paragraph 2?| A．Stress. | B．Choose. | C．Make use of. | D．Find out. |
| A．It was the largest living thing at that time. | B．It was a plant-eating dinosaur. |
| C．It lived at least 220 million years ago. | D．It was the earliest dinosaur in the south. |
| A．They had enough food. | B．They had a strong body. |
| C．CO2 is harmless to them. | D．They were not afraid of dry climates. |
| A．The spread of small plants. | B．Migration of dinosaurs. |
| C．The change of the atmosphere. | D．An increase in rainfall. |
【推荐1】Agriculture may feed the world, but it is also contributing to environmental problems. Agriculture production uses about 70% of the Earth's fresh water and makes up about a third of greenhouse gas emissions. But it doesn't have to. Farming is moving inside, and farmers aren't exactly what they used to be.
Take for example Grover and Phil, two robots, or farmers of the future, working at Iron Ox, a farm tech company in Silicon Valley, planning to set up farms around the country in or- der to grow crops closer to consumers in a greener way. “We have different robots that are looking after the plants. They can check and scan them for issues, and change the amount of nutrients plants get and the amount of water they get, "explained Brandon Alexander, CEO of Iron Ox.
Iron Ox’s method is very different from what Alexander calls the“spray (喷洒) and pray” approach to agriculture on a Texas farm, where he grew up and more chemicals create more quantity at the expense of quality. “Besides, a lot of the water in field farming gets just washed out and never actually reaches the plants. And when 70% of your fresh water is going into farming, only 10% of that actually reaches the plants. It's just generating a lot of waste, ”he said. However, the indoor farming allows farmers to grow any crop at any time, regardless of climate change. It also uses hydroponics(无土栽培) , growing crops without soil so water goes directly to the roots.
“In the indoor farming industry today, even with all the investments into it, these investments are a drop in the bucket(桶) in spite of the great potential of this new industry,” he added.
Iron Ox is now magnifying its business in more states. Alexander says the company will produce about 100 times more produce over the next 18 months than it's currently producing to satisfy greater needs.
1. Which of the following may be Grover and Phil's work?| A．Producing nutrients for crops. |
| B．Curing plants of their diseases. |
| C．Watering plants scientifically. |
| D．Delivering produce to consumers. |
| A．Chemicals contribute a lot to the quality of crops. |
| B．Hydroponics is impractical in growing crops now. |
| C．It takes much more time for crops to grow indoors. |
| D．Indoor farming has advantages over traditional one. |
| A．It causes a waste of more water. |
| B．It needs buckets to grow crops. |
| C．It is unlikely to attract investments. |
| D．Its investments are far from enough. |
| A．Expanding. |
| B．Changing. |
| C．Reducing. |
| D．Quitting. |
【推荐2】New research has found that grey seals can simulate(模仿）human speech and songs. The study carried out by Dr Amanda Stansbury and Professor Vincent Janik,at the University of St Andrews,found that grey seals use the same sound production system as humans due to having similar vocal tracts(声道）。
Three young grey seals-Zola,Gandalf and Janice-were monitored from birth by Stansbury and Janik to determine their natural talents.Once this process was complete, the researchers began teaching the seals to simulate common seal sounds or noises a seal might normally hear from a herd mate in the wild.Fish was used to encourage the seals to come out of the water and sing a series of notes.Stansbury would record the seals'own sounds and play them back.The seals quickly learnt that if they sang back the same notes, they would be rewarded with fish.
Once the seals were familiar with this process and could easily copy these basic sounds,Stansbury and Janik used higher and longer tones and unfamiliar vowels from human speech.The seals were then rewarded for matching these new sounds.Stansbury even used some combinations to simulate songs that no seal would be expected to produce under natural circumstances.Zola had a gift for copying up to ten notes of songs such as Twinkle,Twinkle,Little Star and the theme song of Star Wars.Gandalf and Janice were better at accurately reproducing combinations of human vowel sounds.
Stansbury said,"I was amazed how well the seals copied the model sounds we played to them.Copies were not perfect,but given that these are not typical seal sounds,it is pretty impressive.Our study really shows how flexible seal voices are."
After one year of working with the researchers,the seal pups were released back into the wild."This study gives us a better understanding of the development of vocal learning,a skill that is important for human language development."Janik believes this knowledge can help to develop new methods to study speech problems.
1. What is the first paragraph mainly about?| A．Grey seals 'learning environments. |
| B．A research finding on grey seals. |
| C．Humans 'sound production system. |
| D．A comparison of humans and grey seals. |
| A．made funny noisesre | B．came out of the water |
| C．repeated the same notes | D．copied typical fish sounds |
| A．It can copy some musical sounds played to her. |
| B．It is good at copying human vowel sounds. |
| C．It is smarter than Gandalf and Janice. |
| D．It likes singing children's songs. |
| A．It shows the living environments of grey seals. |
| B．It leads to a better understanding of human vocal system. |
| C．It raises an awareness of the need to protect grey seals. |
| D．It brings inspirations for research on speech problems. |
【推荐3】When you eagerly dig into a long-awaited dinner, it’s traditionally believed that signals from your stomach to your brain stop you eating so much. However, a research team recently discovered that it’s our sense of taste that immediately pulls us back from eating food overly on a hungry day. Stimulated by the perception of flavor, a set of brain cells become active to quickly curtail food intake.
Previous studies have suggested that the food taste may control how fast we eat, but it’s been impossible to study relevant brain activities during eating because brain cells that control this process are located deep in our brains, making them hard to access or record in an awake animal. New techniques developed by the team allowed for the first-ever imaging and recording of a brainstem structure critical for feeling full, called NTS, in an active mouse.
The new study found that when researchers put food directly into the mouse’s stomach, brain cells called PRLH were activated by signals from the gut (消化道), in line with traditional thinking. However, when they allowed the mice to eat the food as they normally would, those signals from the gut didn’t show up. Instead, the PRLH brain cells switched to a new activity pattern that was entirely controlled by signals from the mouth. “It’s astonishing that these cells were activated by the perception of taste,” said researchers. “It shows that there are other components of the appetite-control system that deserves our attention.”
The PRLH-activated slowdown also makes sense in terms of timing. The taste of food allows PRLH to switch their activity in seconds. In contrast, another group of brain cells, called CGC, takes several minutes to respond to signals from the gut. The good thing is that CGC can hold back hunger for a much longer time. These two sets of brain cells interact to work together: one uses taste to slow down eating, while the other signals that you are full.
Understanding how body signals regulate appetite could improve weight-loss programs for the overweight by making use of interactions between signals from different brain cell sets.
1. What does the underline word “curtail” in paragraph 1 probably mean?
| A．Activate. | B．Limit. | C．Expand. | D．Assist. |
| A．Inadequate technologies. |
| B．Inefficient funds. |
| C．Unqualified professionals. |
| D．Improper methods. |
| A．They helped stimulate the mice’s appetite. |
| B．They encouraged the mice to speed up eating. |
| C．They were activated by signals from the mouth. |
| D．They were controlled by signals from the stomach. |
| A．To slow down eating speed. |
| B．To improve the digestion system. |
| C．To extend the feeling of fullness. |
| D．To interact with signals from taste. |
【推荐1】Did you watch the popular TV series Meet Yourself during your winter vacation? In the TV series, the heroine Xu Hongdou travels to a village in Yunnan province and volunteers at a local cafe. She gets free meals in return. As the show finds a growing audience, volunteer travel - an old-yet-modern form of travel similar to Xu*s type of work - has attracted more attention.
Volunteer travel refers to taking a trip where all or part of the purpose of the trip is to participate in an arranged service opportunity to help others, according to Wise Tour, an online provider of tourist information.
These volunteer trips are usually arranged by church organizations, human interest groups or nonprofit organizations, and they take form of equal exchanges. During the trip, volunteer travelers often provide services like teaching, cooking, animal caring, and cultural activities. In exchange for their help, the volunteers may get free or discounted accommodation, meals and laundry (洗衣服务 )，activities, or classes.
It seems as if these long journeys could only be made possible in recent years by modern transportation. Nevertheless, volunteer travel dates back to the 1960s, when Alec Dickson and his wife Mora from the UK founded Voluntary Service Overseas (VSO), an international volunteer organization.
Traditionally, the volunteer activities take place in a foreign country. However, just as what Meet Yourself describes, more volunteer trips have taken place within the same countries or regions the volunteers originate from in recent years. Sanlian Lifeweek magazine commented that volunteer projects in rural areas are now attracting more urban visitors as a break from the fast and stressful pace of urban living. Yang Yan, a founder of a volunteer platform, told the magazine that it has indeed been a growing trend for urban residents to volunteer in rural areas.
People try volunteer travel for several reasons. By working voluntarily while traveling, travelers may make a real, positive impact on the world. The services volunteers provide can be through charities with lower costs for the communities they serve. Another benefit of volunteer travel is that it helps urban dwellers(居民)to get a taste of rural life. For those who are sick of urban pressure but can’t make up their minds whether to move permanently to the countryside, volunteer travel can be a solution. In this way, as Yang comments, travelers can catch some relief from their busy lives, while rural communities also benefit by receiving more customers for local tourism industries and temporary high-quality labor.
1. Why does the author mention Meet Yourself in the beginning of the article?| A．To introduce a new way of travel. |
| B．To raise readers’ interest in the TV series. |
| C．To show the popularity of this TV series. |
| D．To lead up to the topic of volunteer travel. |
| A．It dates back to the 19th century in the UK. |
| B．It combines travel with meaningful work to help others. |
| C．It requires travelers to be highly educated. |
| D．Travelers can earn money on their trips. |
| A．A new trend of volunteer trips. |
| B．Different views on volunteer trips. |
| C．The significance of volunteer trips. |
| D．The current development of volunteer trips. |
| A．To follow a new trend. | B．To support the rural tourism industry. |
| C．To give back to society. | D．To get away from the worries of city life. |
【推荐2】Physical activity is important in preventing cardiovascular(心血管的) disease in young people so long as they don’t undertake very intense activity on days when air pollution levels are high, according to a recently released study.
Until now, little has been known about the relationships between the health benefits of physical activity taking place outdoors and the potentially harmful effects of air pollution. Previous research by the authors of the current study had investigated the question in middle-aged people at a single point in time, but this is the first time that it has been investigated in young adults aged between 20—30 years over a period of several years. In addition, the researchers wanted to see what happens when people increase or decrease their physical activity over time.
At each health check-up, the participants completed a questionnaire asking about their physical activity in the past seven days and this information was changed into units of metabolic equivalent task(MET, 代谢当量任务) minutes per week(MET-mins/week). The participants were divided into four groups: 0, 1—499, 500—999 and 1000 or more MET-mins/week. People are recommended to do 500—999 MET-mins/week and this can be achieved by; for example, running, cycling or hiking for 15—30 minutes five times a week, or brisk walking, doubles tennis or slow cycling for 30—60 minutes five times a week.
The researchers used data to calculate annual average levels of air pollution, in particular the levels of small particulate matter that are less than or equal to 10 or 2.5 microns in diameter, known a PM10 and PM25.
Overall, the results show that physical activity is associated with a lower risk of developing cardiovascular disease among young adults. However, when air pollution levels are high, exercising beyond the recommended amount may offset or even reverse the beneficial effects. The study cannot show that air pollution causes the increased cardiovascular risk, only that it is associated with it.
1. What can we know from Paragraph 2?| A．Outdoor physical activity harms our health. |
| B．Exercising isn’t advised on serious air pollution days. |
| C．A first in-depth survey has been done on young adults. |
| D．Middle-aged people have been the ideal research target. |
| A．By doing research on young adults. |
| B．By collecting PM10 and PM2.5 data. |
| C．By making experiments on middle-aged people. |
| D．By studying a questionnaire on physical activity. |
| A．Air pollution leads to cardiovascular disease. |
| B．Cardiovascular disease relates to air pollution. |
| C．More physical exercise benefits young people. |
| D．Young adults seldom develop cardiovascular disease. |
| A．Physical activity & air pollution: when to do more or less physical activity. |
| B．Physical activity & health benefit: how to prevent cardiovascular disease |
| C．Physical activity & air pollution: what to do with high air pollution levels |
| D．Physical activity & health benefit: how to maximize the health benefits of exercising |
The influence of the mind on how well we feel is the basis of what is known as the placebo effect. A placebo (which is Latin for “I shall please”) is a harmless, inactive substance. Patients are sometimes given placebo pills and begin to feel better because they believe that they have been given real drugs and expect to respond to them. The placebo effect is very strong: research on pain suggests that up to 30% of the effect of most painkillers is a placebo effect.
So if it is so powerful, why don’t doctors use it today?
According to Dr Persaud, they really do. “All these things like seeing a doctor, going to a hospital, and being scanned(扫描) have a very strong placebo effect,” he says.
1. According to the first paragraph, if you feel ill.
| A．you don’t need to see a doctor |
| B．it doesn’t necessarily mean that you’re physically ill |
| C．you are in good condition |
| D．it is obvious that you suffer from a serious disease |
| A．a sound mind is less important than a good health |
| B．our mind has a strong effect on our body |
| C．our physical health has nothing to do with our mind |
| D．mental health mainly depends on our physical health |
| A．may make patients feel worse |
| B．are not effective pills |
| C．are not real drugs |
| D．can relieve all kinds of pains |
| A．is dressed in white | B．has a physical exam |
| C．takes placebo pills | D．sees a doctor |
