C

    How often do you check your phone? According to a study led by Nottingham Trent University in Britain, the average person looks at their phones 86 times a day. Updating their status on social media platforms also made people reach for their electronic companion frequently.

    Even the participants thought that was a lot: this figure is twice as often as they thought they did. Our phones might be shaping our behavior more than we realize. Do you actually look at your surroundings more than at your phone? Is it rude to check your phone when someone is talking to you?

    Sherry Turkle interviewed hundreds of college students about this. She's a professor of social studies at the Massachusetts Institute of Technology. They talked about something they called "the rule of three".

    The rule has to do with being considerate to others despite the allure (诱惑力) of the little flat box. Turkle explains: "If you go to dinner with friends, you don't want to look down at your phone until you see that three people are looking up in the conversation. So there's a new rule where you don't look down unless three people are looking up in order to keep a little conversation alive."

    Actually, if you are clever enough you might use your phone as a tool to connect with people next to you. Sharing a bit of your life with them can bring you closer together. And you can also invite everyone to take a selfie (自拍照) with you.

    But the best thing to deal with mobile phone addiction is to go cold turkey and leave the machine behind occasionally or just switch it off and keep it firmly in your pocket for a while.

    Teens are certainly confusing and complicated, but there is one thing that's clear about them: More than anything else, they want to fit in with their peers. They want and need to stay connected. Without connection, they feel lonely, anxious and sad{#blank#}1{#/blank#}

    Teens, like adults, run into all sorts of dilemmas with their friends. Friendships are neither all good nor all bad. As an adult, you have experience with these sorts of friends and have made your own adjustments in these relationships. Given both your own life experience and your concern for your teens, you're in an excellent position to help your teens set boundaries with friends. Certainly, some friendships are worth maintaining, while some are not,{#blank#}2{#/blank#}There are many ways you can help your teens handle these relationships effectively. Here are some steps I would suggest taking:

    Teach your teens to label their feelings. They need to know what it is that they are feeling first to effectively set limits and boundaries with friends. Help them label setbacks, exhaustion, disappointment and anger. This is no small task. Many kids struggle with labeling their feelings.

     {#blank#}3{#/blank#}If they sense that something is wrong in a friendship, they're probably right, end they need to quit it as soon as possible.

    Explain to your teens that they can't be all things to all friends. And let them know that friendships are most likely to grow and continue if they feel good about them.

    Discuss different ways to set boundaries. Explain to your kids that just as it makes sense to say yes at times{#blank#}4{#/blank#} Just as it's fine to spend lots of time with a friend during the week, it's equally OK to spend less time with the same friend when that friend is being too demanding or needy.

    Look at your behavior in relationships{#blank#}5{#/blank#} They are quietly watching your every move. So .make sure you're setting a good example for them to follow in your relationships as well.

A. so they need to tel what are right relationships

B. and they shall find their way ou of those friendship

C. Keep in mind that you are your teens' most important role model

D. Remind your teens of bad relationships

E. it's also socially acceptable to say no at other times

F. Encourage your teens to mind their feelings and follow the sixth sense

G. but they may get exhausted by their friendships as well

    Most groups of plants and animals are richer in species and more plentiful near the equator. In the ocean, that holds true for cold-blooded predators(掠食者). But warm-blooded predators are more diverse toward the poles and noticeably missing from several warm hot spots. Why?

    John Grady, an ecologist, and his team considered the possibility—warm-blooded animals need a lot to fuel their metabolism(新陈代谢). Perhaps colder waters are just richer in small fish? But they found that at higher, colder places, there isn't actually much more food around. It's more that warm-blooded animals are eating a much bigger share of it than their cold-blooded competitors.

    The real explanation is simple. An animal's speed, swiftness, and intelligence depend on its metabolism, which in turn depends on its temperature. Since birds and mammals can keep heating their bodies in icy conditions, they remain fast and attentive. By contrast, the fish they hunt become slower and duller. At some tipping point of temperature, seals, dolphins, and penguins start out swimming their prey(猎物). They become more likely to come upon targets and outpace the cold-blooded predators of their own.

    In Grady's words, "Warm-bodied predators are favoured where preys are slow, stupid and cold." That's why sharks and other predatory fish dominate near the equator, but colder waters are the kingdom of whales and seals. By keeping food to themselves in the poles, these creatures can then specialize on specific types of prey, which makes them more likely to split into separate species. The killer whales of the North Pacific, for example, include mammal-eating transients and fish-eating, year-round residents.

    But the world is changing. It's likely that the surface of the oceans will warm by 2 to 3℃ within this century. Grady's team estimates that every time the ocean's surface warms by 1℃, populations of sea mammals will fall by 12%, and populations of seals and sea lions will fall by 24%.

    But "predictions are hard," Donna Hauser from the University of Alaska Fairbanks notes. "Polar bears are losers of a warming world, but some populations are still doing well. Some groups of whales have changed the timing of their migrations; others are hunting in deeper, colder waters. These changes might make sea mammals more adaptable to changing climates. Maybe they just need to find the places where fish remain slow, stupid and cold."

    In earliest times, men considered lightning to be one of the great mysteries (神秘的事物)of nature. Some ancient peoples believed that lightning and thunder were the weapons (武器) of the gods.

    In reality, lightning is a flow of electricity formed high above the earth. A single flash of lightning 1.6 kilometres long has enough electricity to light one million light bulbs (灯泡).

    The American scientist and statesman, Benjamin Franklin, was the first to show the connection between electricity and lightning in 1752. In the same year he also built the first lightning rod (避雷针). This device (装置物) protects buildings from being damaged by lightning.

    Modern science has discovered that one stroke (闪击) of lightning has a voltage (电压) of more than 15 million volts (伏特). A flash of lightning between a cloud and the earth may be as long as 13 kilometers, and travel at a speed of 30 million meters per second.

    Scientists judge that there are about 2,000 million flashes of lightning per year. Lightning hits the Empire State Building in New York City 30 to 48 times a year. In the United States alone it kills an average (平均数) of one person every day.

    The safest place to be in case of an electrical storm is in a closed car. Outside, one should go to low ground and not get under tress. Also, one should stay out of water and away from metal fences. Inside a house, people should avoid open doorways and windows and not touch wires or metal things.

    With lightning, it is better to be safe than sorry?

The Big Ben is located in the tower at the eastern end of the Houses of Parliament, Westminster, Greater London. It was designed by Edmund Beckett and Baron Grimthorpe.

The Big Ben is very famous throughout the world, but nobody really knows why it is called Big Ben. There are two hearsays about this. Some people say that it was named after Benjamin Caunt, a boxer, who was called Big Ben. More people believe it was called after Welshman, Sir Benjamin Hall. He was the commissioner(特派员)of the work at the time of its installation in 1859. A story was told that during a debate in the Commons on what to call the bell, Sir Benjamin was about to give his ideas when a MP who sat behind the front bench shouted, "Let's call it Big Ben!" Then this name came into being.

The bell hasn't gone through a smooth road since the beginning of its design. Because there was great disagreement about the design of the clock. It took fifteen years to build. In 1857, the bell was completed and tested on the ground, but a four-foot crack appeared and the bell had to be cast again. Finally, the clock started ticking on 31 May, 1859, and struck its first chime(报时)on 11, July. Then in September, the bell cracked again. It was silent for four years but was eventually turned a quarter of a revolution(旋转). In this way, the crack was not under the striking hammer. Craftsmen made a square above the crack to stop it growing longer and it can still be seen today.

The Big Ben is famous not only for its 13-ton weight, but also for its accuracy(准确性) which is a result of its precise mechanism(机械装置). Even one extra penny's weight on the balance will cause a gain of two fifths of a second in twenty-four hours. Although there have been several problems, the bell is still striking today. Its chimes can be heard all over the world on the B. B. C.

Deep below the ground, radioactive elements break up water molecules(分子), producing substances that can fuel subsurface life. This process, known as radiolysis(辐射分解),has supported bacteria in tiny cracks filled with water on Earth for millions to billions of years. Now a study published in Astrobiology shows that radiolysis may have supported life in the Martian subsurface. 

Dust storms, rays in the universe and solar winds ruin the Red Planet's surface. But below, some life might find shelter. "The best survival habitat on Mars is the subsurface," said Jesse Tarnas, a planetary scientist at NASA, Examining the Martian underground could help scientists learn whether life existed there. And the best subsurface samples available today are Martian meteorites(陨石) that have crash-landed on Earth.

Tarnas and his colleague looked at the minerals on the Martian surface and how many radioactive elements there were, using satellite and rover data, They used computers to simulate(模拟) radiolysis to see how efficiently the process would have generated life-supporting hydrogen gas and other chemical substances. They reported that if water was present, radiolysis could have supported life for billions of years and perhaps still could today. 

Scientists had previously studied Mars radiolysis, but this marked the first estimate using Martian rocks to see how habitable Mars underground might be. Tarnas and his colleagues also evaluated the potential richness of life in Martian underground.They found that up to a million bacteria could exist.in just one kilogram of rock, The most habitable seemed to be the southern highlands of Mars, which is the most ancient area on Mars, according to Tarnas.

"Underground life would require water and it remains unknown if groundwater exists on the planet," says Lujendra Ojha, a planetary scientist at Rutgers University. Determining whether the Martian, subsurface contains water. will be an important next step, but this investigation helps to motivate that search, Ojha says, "Where there is groundwater, there could be life."