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.

    Do equations and historical( 历史的) facts give you a headache? A change in the school timetable(课程表) may be the cure.

    This  suggestion  is  based  on  a  recent  study  carried  out  by  scientists  from  Royal  Holloway, University of London, the UK. They found that teenagers could get higher marks in math if they studied in the mornings and better grades in history if they were taught in the afternoons.

    The researchers studied students' grade reports, class timetables and absence rates( 缺席率) at a middle school in Bulgaria over nine years. The results showed that when teenagers had math classes earlier in the day, they scored about 7 percent higher in tests than when taught in the afternoon. Lower-ability students feel stressed most when they were studying math in the afternoon. In history, students taught in the afternoon scored about 6 percent higher than when they were taught in the morning. However, there was no sign that similar patterns( 模 式 ) work for other subjects such as languages or geography.

    Velichka Dimitrova, who did the study, said the findings show that we perform( 表 现 ) better at different times of the day. “In the morning, our brains are better and fresher, so we are better at doing something like problem solving, where we require more speed and attention” Dimitrova told The Telegraph. “In the afternoon, it seems that this process slows down. On the other hand, history is more suitable for the afternoon, when we are more creative and open to discussion,” she said. Subjects such as foreign languages require both memory and creativity. This is perhaps why the time of day had no influence on language learning.

    Time-of-day influences such as these are believed to have something to do with the body clock.

    This is the system in our bodies that controls when we need to sleep. Some schools in the US and UK have tried later school starting times for teenagers, whose body clocks change as they grow into adults. Dimitrova believes schools should jump at this chance to improve their students' performance just by changing their timetables.

    Now, it seems that artficial intelligence （人工智能）is becoming more and more popular in our life, and it has greatly influenced the ways we live, work and play. Can you imagine that you can play table tennis with a robot one day?

    Recently, a scientist has invented a special robot that can be a table tennis coach. That means people can practice table tennis not only with humans but also with a robot.

    Named Forpheus, the smart table tennis robot is quite special. It can study the movements of human players and the speeds of the ball. In this way, it can exactly judge (判断) the player' skill levels (水平). Then it uses the information to change the ways to play. If the player are just beginners, Forpheus will play in a slow and easy way, but if the players are better ones, the robot will play in a faster and more difficult way. What's more, while playing, it encourages players to try their beat with words like "Good job!", "Come on!" and so on. At the same time, it gives some good advice to improve their skills. So it is both a good partner and a clever coach.

    Science and technology is developing quickly these days and it's hard to imagine what will happen in the future. "In the next 20 years, it will be possible that one robot teaches another to play table tennis or even invents another one!" Takuoya, the inventor of the robot, said.

    Did you know that each day one person in the USA throws away 4.4 pounds of rubbish? Almost every month, we throw away our own rubbish in packaging alone. Packaging (including boxes, bags, etc.) comes to our homes with the things we have bought. Several weeks ago, the TV news said that in a city in Italy tons of rubbish were piled up in the streets, and the smell was rather terrible. What can we do to help? We should get to know the following Rs.

    Reduce To reduce means to make less rubbish. That is one of the first things we all should do for the environment. Reduce your rubbish by doing things like packing your lunch in reusable containers(可再利用的容器), taking smaller portions(份) at dinner so you don't waste food when you have had enough, writing on both sides of paper, and using less water when taking a shower.

    Reuse to reuse is to use things again. Think about the bags you get from the shop. They can be reused to carry your lunch, to hold your rubbish, or to collect used cans. You can even take them back to the school next time to carry your things instead of getting a new bag!

    Recycle(回收利用) Recycling is an important part of keeping our planet clean and green. It can also save energy. Be sure that you don't throw things in the rubbish bins that can be recycled to make something else Paper, plastic, cans and bottles can all be recycled. But food, electrical waste and mobile phones cant. When you are not sure whether something can be recycled, go to your parents and teachers for advice.

Follow the three Rs, and every one of us can do something to save the Earth. It is also the best way to save ourselves.