Mosquitoes have an extraordinary ability to find humans far away and fly straight to their skin. Mosquitoes can do more than cause an itchy (发痒的）wound. Some mosquitoes spread several serious diseases, including Dengue, yellow fever and malaria.

    Over one million people worldwide die from these diseases each year. New research now shows how mosquitoes choose who to bite.

    Mosquitoes need blood to survive. They are attracted to human skin and breath. They smell the carbon dioxide gas, which all mammals breathe out. This gas is the main way for mosquitoes to know that a warm-blooded creature is nearby.

    But mosquitoes also use their eyes and sense of touch. Michael Dickinson is a professor at the California Institute of Technology. His research shows how these small insects, with even smaller brains, use three senses to find a blood meal.

    Michael Dickinson's team used plumes—a material that rises into the air of carbon dioxide gas into a wind tunnel (隧道). They then used cameras to record the mosquitoes. The insects followed the plume.

    Then, the scientists placed dark objects on the lighter colored floor and walls of the tunnel. Mr. Dickinson said, at first, the mosquitoes showed no interest in the objects at all. “What was quite surprising is that the mosquitoes fly back and forth for hours. These are hungry females and they completely ignore the objects on the floor and wall of the tunnel. But the moment they get a hit of CO₂, they change their behavior quite obviously and now would become attracted to these little visual blobs (斑点).”

    This suggested to the researchers that a mosquito's sense of smell is more important in the search for food. Once mosquitoes catch a smell of a human or animal, they also follow visual signals.

    Two recent studies have found that punishment is not the best way to influence behavior.

    One showed that adults are much more cooperative if they work in a system based on rewards. Researchers at Harvard University in the United States and the Stockholm School of Economics in Sweden did the study.

    They had about two hundred college students play a version of the game known as the Prisoner's Dilemma. The game is based on the tension between the interests of an individual and a group. The students played in groups of four. Each player could win points for the group, so they would all gain equally. But each player could also reward or punish each of the other three players. Harvard researcher David Rand says the most successful behavior proved to be cooperation. The groups that rewarded the most earned about twice as much in the game as the groups that rewarded the least. And the more a group punished itself, the lower its earnings. The study appeared last month in the journal Science.

    The other study involved children. It was presented last month in California at a conference on violence and abuse（虐待）. Researchers used intelligence tests given to two groups. More than eight hundred children were aged two to four the first time they were tested. More than seven hundred children were aged five to nine. The two groups were retested four years later, and the study compared the results with the first test. Both groups contained children whose parents used physical punishment and children whose parents did not.

    The study says the IQs of the younger children who were not spanked were five points higher than those who were. In the older group, the difference was almost three points. The more they are spanked, the slower their mental development.

    Every day I see advertisements in the newspapers and on the buses claiming that it is easy and quick to learn English. There is even a reference to William Shakespeare or Charles Dickens to encourage learners even more. When I see advertisements like this, I don't know whether to laugh or cry. But many people must believe these ridiculous claims, or else the advertisements would not appear.

    Of course it is clear that students who go to England to learn English have a great advantage over others, but too many cannot afford to do so. Some go to the opposite extreme and think they can teach themselves at home with dictionaries. But it is wrong to assume that each word in English has a precise equivalent in another language, let alone produces good pronunciation and intonation.

    Most teaching is still based on behaviorist psychology. Behaviorists are fond of making students repeat phrases and making sentences. If we were parrots or chimpanzees, these methods might be successful. A large number of theorists seem to think it is a pity we aren't, because it would make it easier to use their methods.

    In my personal opinion, no one can ever learn to speak English or any other language unless he is interested in it. Human beings, unlike parrots and chimpanzees, do not like making noises unless they understand what the noises mean and can relate them to their own lives. It is worth remembering that language is a means of communication. What they listen to and read cannot be a formula. It must be real.

    There is another relevant point worth mentioning here. We need other people to talk to and listen to when we communicate. They can work with us and practice the unfamiliar forms with us in real situations, talking to each other about real life language.

    Planning to get away? Think passport first

    If you're planning to get away from it all this year, you should think passport first. Checking you have a valid passport before you book your trip takes minutes but could save you the trouble and cost of not being able to go.

    Renewing (更新) your passport before it runs out

    You can renew your passport up to 9 months before it can no longer be legally used. So take the time now and save the tears later.

    Applying for a passport for the first time

    Our eligibility (资格) checks mean that it takes a minimum of one week to issue (颁发) a passport. So make sure you don't leave it to the last minute, and apply in plenty of time.

    Help with your application is just around the corner

    Selected Post Office branches and Worldchoice travel agents offer a Check and Send service that helps you with your application. It's convenient and you should receive your passport within 2 weeks.

    If you need to apply for or renew a passport, you can either:

    Pick up a Passport Application Form at Selected Post Office branches and Worldchoice travel agents.

    Or call the Application Form Request line on 0901 4700 100 or visit www.passport.gov.uk

    If your need is urgent, call 0870 521 0410 for an appointment at one of our offices. We can't guarantee to see customers without an appointment.

    From 14th January a guaranteed same day (passport renewals only) or one week service will be available from passport public counters.

    *Calls will be charged 60p per minute and the cost per call should not normally be more than 90p.

    *Calls are charged at national rates.

    Traveling by subway can sometimes be quite an adventure, especially during rush hour. There are the times when you have to avoid cups of coffee that could spill (溅) on you. The smells of some passengers' food are very strong, too. According to the Beijing subway passenger regulations, which went into effect on May 15th, passengers except babies and the sick are no longer allowed to eat or drink on the subway. Violators (违反者) who do not stop after being asked to will be asked to get off. The violation will also be recorded in the violators' credit record.

    Some support the rule. The reason is that the smell of food and drink can annoy other passengers. "The smell of food fills the carriage, causing people discomfort, especially in the hot summer. Besides, eating on the subway produces rubbish. And on subway trains, people often spill their drinks," said Zheng Yiou, 17, a student from Hefei.

    However, others question this rule. "Some citizens live so far from their work places that they have limited time to have breakfast before they go to work. Eating while they travel saves them time and decreases the chance that they will be late for work," He Songlin, a 17­year­old student from Chengdu said, "And some people, like those with low­ blood sugar levels, get sick if they can't eat when they must."

    Other Chinese cities like Nanjing and Chengdu have similar regulations. Some foreign cities also ban eating and drinking on the subway. For example, eating and drinking have long been banned on the subway in Washington DC. Singapore fines people who eat or drink on the subway up to 500 Singapore dollars, which is RMB 2,417 yuan.

    Chen Yanyan, a professor from Beijing University of Technology, believed we should consider the need of some people to eat or drink on the subway. "Commuters (上班族) and travelers are sometimes too busy to eat. Maybe we could learn from Tokyo, where there are many subway stations equipped with services, allowing passengers to eat and drink," she said.

Sullivan calls her right arm her "little arm". The 10-year-old was born with that arm less than half the 1 size. She has no elbow and tiny fingers to 2 things. However, it never discouraged her. This 3 kid could always find a way to make that little arm 4 for her. Until recently, riding a bike has proved out of her reach. But that might soon change 5 some college students.

Sullivan's grandparents saw a local news about Siena College students making a prosthetic (假肢的) hand for a little girl using the school's 3D printer. They went to see if her granddaughter could be a 6 for a new arm like that girl. However, there was a 7 when the grandparents asked if the college group could help Sullivan, as the design was for limbs (肢体) 8 an elbow or wrist.

Fortunately, Kristin, a junior engineering major said yes. She and her team couldn't 9 a perfect solution, but they promised to try. They met Sullivan from time to time to measure and test the design, 10 the initial plans to fit Sullivan's little arm. They've worked for almost a year to build Sullivan a solution. The task has been one of 11 and creativity,12 by kindness. "Sometimes you get 13 , but she is so excited," Kristin said. "Her motivation and her strength, 14 our team along."

On May 4, Sullivan received her arm. She also received a(n) 15 surprise: a new bike.