A student is learning to speak British English. He wonders: Can I communicate with Americans? Can they understand me? Learners of English often ask: What are the differences between British and American English? How important are these differences?

    Certainly! There are some differences between British and American English. There are a few differences in grammar. For example, speakers of British English say “in hospital” and “Have you a pen?” Americans say “in the hospital!” and “Do you have a pen?”. Pronunciation is sometimes different. Americans usually sound theirs in words like “bird” and “hurt”. Speakers of British English do not sound theirs in these words. There are differences between British and American English in spelling and vocabulary. For example, “color” and “honor” are British, “color” and honor” are American.

    These differences in grammar, pronunciation, spelling and vocabulary are not important, however. For the most part, British and American English are the same language.

    The loud noise of the cars or the sound of a plane can force its way into the deepest forest, yet it's not only humans that are bothered by the noise.

    Bioacoustician Bernie Krause has been studying the effect of noise pollution on wildlife, and has come across some interesting behaviors, especially among animals that communicate by sound, like humans. Birds use sound to communicate, but in noisy places, these animals have to shout over the natural noise to be heard.

    Krause mentions a study of nightingales(夜莺) to explain what he means. The birds responded to（回应） traffic noise by singing louder and louder until they actually went beyond noise pollution standards in the city. To belt out (sing loudly) their songs, they increased their lung pressure fivefold, but scientists say that this is not dangerous for the birds themselves.

    Studies show that sudden noise can cause certain birds to leave their nests, leaving the young to their enemies. One study also showed that songbirds that nested close to busy motorways were much less productive than those that nested farther away. Mammals（哺乳动物）too are affected(影响). A recent study showed that nursing caribou（驯鹿） responded to plane noise by not producing enough milk to feed their young.

    In some cases noise pollution can actually help some animals while harming others. Toads（蟾蜍）and frogs are known to sing in union（同步发声）so that no predator (their enemies) can catch them. Krause found that when planes flew overhead and disturbed the toad's song, they lost their union, and it took them 45 minutes to get it back again. That gave their natural enemies plenty of time to find and catch individual toads by sound.

    According to Kruse, 'Not only will noise pollution bother wildlife, but it won't help our lives either.'

    Throughout the world, parents talk differently to babies than they do to adults. With their young kids, parents use baby talks, featuring long pauses and a roller coaster of pitch（音高）changes.

    While parents may feel a bit silly using baby talks, they shouldn't in fact. Babies not only prefer listening to them, but they also learn new words more easily from them. By highlighting the structure of speech, such as the differences between the vowels（元音）“a” and “o”, baby talks help babies translate sounds into meaningful units of language.

    Actually, the timbre（音色）plays a role. The timbre of an instrument clearly affects how we experience music, but its role in language is less obvious. Looking into the timbre of baby talks, researchers made some surprising discoveries. In a new study published in Current Biology, researchers reported for the first time that mothers shifted their overall vocal timbre when speaking to their babies, as if they were changing their voice into a different instrument to address these unique little listeners.

    In the Princeton Baby Lab, where researchers study how children learn, they recorded English-speaking mothers while they talked with their 7-to-12-month-old babies and while they spoke to an adult experimenter, and found that adult-directed and baby-directed speech had consistently different timbres.

    Most surprising, in a second sample of non-English-speaking mothers, researchers found that this timbre shift was also highly consistent across nine diverse languages. This suggests these timbre shifts may represent a universal form of communication with babies.

    Being able to identify baby talks across multiple languages could give us rich information about the amount and type of language children hear at preschool across different cultural environments. This could help researchers and educators predict and improve outcomes such as vocabulary and success at school.

    Parents should feel self-conscious about their own baby talks: with them they're helping their baby learn.

    Some of the people who created many popular apps are telling kids to put their phones away — at least, a bit more often. The Center for Humane Technology is made up of people who used to work for big tech companies like Google, Facebook and Twitter. Now they want kids to stop using those apps and websites so much.

    In early February, the center started a campaign called The Truth About Tech. Its goal is to teach students, parents and teachers about the dangers of spending too much time on smart phones and computers.

    According to studies about kids and technology, more than 95 percent of elementary school-aged children spend at least part of every day using a computer or smart phone. About 78 percent of teens check their phones every hour, and more than half of them sleep with their phones in case they get a call or message during the night.

    The Center for Humane Technology says that the apps and websites we use every day are purposely designed to keep us chatting, playing or watching online as much as possible. That includes social media like Snapchat, Instagram, Facebook and Twitter, websites like YouTube and online games. It also says that the tech companies talk only about the good aspects of their products and don't mention the side effects.

    Some physical problems, like headaches, eyestrain (眼疲劳), and neck pain are caused by using phones or computers too much. Students spending too much time online may find it hard to be focused on school work. Children and teenagers are more likely to have these problems because their brains, bodies and social skills are still developing.

    One goal of The Truth About Tech campaign is to make sure that kids understand how technology affects them so they can make better decisions. The people behind the campaign also want governments and the tech companies themselves to take steps to protect children. When the leaders of the big technology companies are designing tech tools for kids, they should think about what they would want for their own children.

    The surface of Venus（金星）has never seemed very hospitable. Temperatures change around 470℃（900℉）, the result of a runway greenhouse effect，and the pressure of its atmosphere, thick with carbon dioxide and sulfuric acid, is some 90 times that of Earth's. Lead（铅）would flow like water on Venus, and water cannot have existed in liquid form for perhaps a billion years.

    Now NASA'S Magellan spacecraft seems to have found one more horror in the nasty landscape: active volcanoes. Last week the space agency released the first detailed map of Venus and the most dramatic images ever made of its surface. The picture offer the best evidence to date that a planet once assumed dead is actually a lively pot of geological change.

    The most amazing image is of Venus's second tallest mountain, Maat Mons, which rises 8km（5 miles）. Most of the planet's many peaks, including 9.5-km-（6-mile-） high Maxwell Montes, look bright in the radar pictures Magellan takes from its orbit above the permanent could cover. That means they are strong reflectors of radar waves. But Maat Mons is dark; like the Stealth bomber, it absorbs much of the radar falling on it.

    This interesting fact, say project scientists, is a strong hint that the mountains has recently been covered with lava. Rock that sits on the surface of mountaintops appears to weather quickly in the hot，chemically reactive atmosphere, creating a soil that is rich in iron sulfide（硫化铁）• It is this mineral, the scientists believe, that can easily be seen on radar. If Maat Mons doesn't have any, it has probably been resurfaced, perhaps within the past few years.

    Such resurfacing has undoubtedly taken place in Venus lowlands: earlier images of the planet showed vast areas that are remarkably free of craters（火山坑）.That would be easy to explain on a Planet like Earth, where cratering from meteor strikes is erased by steady erosion. But while there is some evidence of wind erosion on Venus, the best explanation for the lack of cratering is periodic lava flow. Magellan has found direct evidence of such flows, including domelike upwellings and hardened streamed of rock trailing down the sides of Venusian peaks. There are also signs of other geologic activities, including dramatic faulting and several distinct incidents of mountain building. But the evidence can't indicate whether they really occurred millions of years ago. The case for active Venusian volcanoes is not yet proved, but Magellan, which is now well into its second complete survey of the planet's surface, may eventually settle the issue.

    With all the recent concern about the environment, people want to see their money used to better the planet. Here are four well-known environmental organizations.

    World Wildlife Fund (WWF)

    The World Wildlife Fund is perhaps one of the best-known organizations for the protection of endangered species and their habitats around the world. They've been around for over 45 years. You can donate through their website worldwildlife.org, join their organization as a member, or adopt an animal through their online adoption center.

    National Geographic Society (NGS)

    National Geographic Society is well-known for their magazine and their specials on TV. The organization itself is one of the longest-running in the world—they've been around since 1888, focus on exploration and conservation of forests, oceans, habitats, species and societies. You chopse to donate through the website nationalgeographic.com，buy something at their online store, or order a magazine subscription.

    National Wildlife Federation (NWF)

Founded officially in 1937, the National Wildlife Federation tries to protect wildlife at all costs. In fact, they believe that having the public educated is the best way to help the environment—the more you know, the more you can protect the world we live in. Donations to the NWF can be made through their website nwf. org or through other options, like matching gifts, workplace giving, or memorial donations.

    Ecology Fund, com

    Set up in 1976，Ecology Fund, com is run on user clicks. Advertisers buy ad space on the site every time someone clicks. The money goes to buy endangered wilderness land to protect it from companies that would destroy it. So far, Ecology Fund, com has bought land in many areas. The best thing about this site is that you needn't donate any money—all you have to do is click.