根据短文理解，完成下列各题。
    In every school there is "top" crowd that sets the pace, while the others follow their lead. For example, if the crowd decides that it is smart to wear bright red sweaters, then very soon everybody is wearing bright red sweaters.
    There is nothing wrong with that, except the fact that for some people bright red sweater is really unsuitable.
    The situation can even become dangerous, if the top crowd decides that it is smart to drink and to drive cars at seventy miles an hour. Then the people who follow the lead are endangering their lives. They are like the sheep being led to the slaughter(屠杀).
    Now it's possible that you have come across situations like these more than once in your life. In fact you probably did something you knew to be wrong one time or another. You may have excused yourself by saying, "Gee, the crowd does it."Well, let the crowd do it, but don't do it yourself. Learn to say "No".
    Develop your own standards(标准)and your own judgment. If you know the crowd is planning something you disagree to, you'd better take the courage to bow out in a polite way. You'll have the satisfaction of standing on your own two feet.

    In some science fiction movies, evil robots refuse to die, no matter how hard people fight back.

    Now science fiction has become science fact. For the first time, scientists have made a robot that can take a beating (挨打) and keep on going. Scientists from Cornell University made the robot, which looks like a spider with four legs.

    Until now, even the most advanced (先进的) robot was almost certain to break down when it was damaged. That is because its computer inside simply doesn't know how to make the machine work after its shape has changed.

    To deal with this problem, the scientists put eight motors (发动机) and two sensors (传感器) that read how the machine is working. They all give signals to the machine's software. Using this information, the computer can then figure out the machine's shape at any moment.

    The new technology is a big advance in robot-making, scientists say, and it's far from scary. It may someday help scientists create better artificial (假的) arms and legs and give new freedom to people who lose them. It might also help scientists understand how people and animals figure out their own sense of place in space.

    “It has been difficult to design robots that can work well when the environment changes or when it's damaged,” says Olaf Sporns of Indiana University in US. “With this work, we are nearer to solving this problem.”

    What do you think the future will be like? Here are some answers from some students.

    Mary: Everyone will have a computer at home. There will also be many machines in the future. Then people will work only two or three days in a week.

    Jack: The weather in the future will be very hot. People can't live on the earth. They will have to look for (寻找) another planet to live on.

    Linda: I think the life in the future will be nice. There will be a lot of flowers and trees. And cities will look like parks.

    Henry: Every family will have a family doctor, so people will be seldom ill (很少生病) They will live to 120 years old.

B

    Most people hope to have a memory which helps them succeed in study, work and life. Can memory be improved? Luckily, hundreds of studies in the past 50 years have already given us a definite answer.

    A healthy lifestyle keeps our brain young and memory sharp. First of all, it is necessary to have a healthy diet. Eating more food rich in B vitamins and vitamin E, such as vegetables and lean meat, helps you have a better memory. Doing exercise can keep your brain alive, too. Proper exercise provides much oxygen for the brain. Running, riding a bike, swimming and even walking two or three times a week are helpful. Moreover, getting enough sleep is important. Only when your brain gets a good rest, can it work well. The healthier your lifestyle is, the better your memory will become. But do not expect a sudden change－it takes a long time to make a difference.

    Memory stills help you remember things better. The following three are the most widely used. Chunking is a way of remembering a piece of information by cutting it into small ones. For example, to memorize a ten-digit telephone number 2127983630, you can divide the digits into three groups: first 212, then 798, and lastly 3630. This method is far more effective than remembering a string of 10 digits. Organization means organizing information into groups of the same kind. For example, trees, grass and flowers are plants; tigers, pandas, horses and cows are animals. Imagery is remembering newly learnt information by using your imagination and connecting it with something that you are familiar with.

    However, memory skills will hardly work if you don't understand the information. What's more, only a regular review can make the memory last long. That is why students are always advised to go over what they have learnt and then use it as regularly as possible.

    Human brains are like muscles that needs nutrients and exercise to become stronger. If you make a few lifestyle changes and try some memory skills, you can certainly improve your memory.

    Cruises are becoming more and more popular, with around 20 million passengers per year now enjoying holidays on board luxury ( 奢侈的 ) ships. More people see a cruise as the perfect way to sit back and do nothing, and enjoy time off work. But what is the effect on the environment of this trend?

    Although it usually takes less energy for a vehicle to move through water than over land, cruise ships are often massive, with the biggest ones carrying up to 6,000 passengers. Moving such large vehicles requires huge engines which bum as much as 300,000 litres of fuel a day. One scientist has calculated that cruise ships create as much pollution as 5 million cars going over the same distance. Because they are out at sea, they also burn dirtier fuel that isn't allowed on land. Unfortunately, no government has control over the amount of air pollution out at sea. Cruises also produce huge amounts of rubbish, and cruise ships aren't usually good at recycling. Waste water from showers and toilets is usually poured directly into the sea - as much per day as from a small town. Waste food from restaurants isn't put into the sea, but still causes problems when brought back to the land.

    Cruise ships also cause difficulties in the cities where they stop. Popular destinations can get five or six ships per day, with thousands of tourists at a time. Good for restaurants? No. Restaurant owners complain that the visitors look around for a few hours and then return to their ship to eat. What's more, the crowds can put off other tourists, who complain that the streets are too busy.

    Some towns have banned (禁止) cruise ships or put a limit on the number that can stop at the same time. People who care about the environment worry that as the cruise industry continues to grow, so will the issues for our planet.

    You don't have to be a scientist to solve big environmental problems. One Dutch designer is finding creative ways to make a change—and he's inviting bikers to join him.

    Daan Roosgaarde, 38, is a designer from Holland. He uses creative ideas to improve city life. For his Smog (雾霾) Free Project, he designed a special tower that cleans air in Chinese parks. In Holland, he designed a shining bicycle path.

    Now Daan and his team are working with engineers at Chinese bike-sharing company Ofo to create a new product for public use. It's an air-cleaning machine connected to a bicycle and is part of the Smog Free Project. In smoggy weather, the machine would breathe in the air in front of the bike and blow out a stream of clean air toward the biker's face.

    It's no secret that air pollution is a big problem for China. In winter, it's common for thick clouds of haze (霾), caused largely by factory production, burning of coal and car emissions (排放物), to cover areas of China.

    In 2016, only one-fourth of Chinese cities met the country's air quality standards, according to a survey of 338 cities nationwide from the Ministry of Environmental Protection.

    "Of course one tower and a few bikes won't solve China's air pollution problem," Daan said, "But smog-free bikes are an exciting idea that will hopefully inspire communities to create greener cities."