Title: To be a {#blank#}1{#/blank#} student

    In the 13th century, the famous Italian traveler, Marco Polo, traveled a long way to China. During his stay in China, he saw many wonderful things. One of the things he discovered was that the Chinese used paper money. In Western countries, people did not use paper money until the 15th century. {#blank#}1{#/blank#}.

    A Chinese man called Cai Lun invented paper almost 2,000years ago. He made it from wood. {#blank#}2{#/blank#} He then put these pieces of paper together and made them into a book.

    {#blank#}3{#/blank#} We use a lot of paper every day. If we keep on wasting so much paper, there will not be any trees left on the earth. Every day, people throw away about 2,800 tons of paper. It takes 17 trees to make one ton of paper. This means that we are cutting nearly 48,000 trees every day.

    Since it takes more than 10 years for a tree to grow, we must start using less paper now. If we don't, we will not have enough time to grow more trees to take the place of those we use for paper.

    {#blank#}4{#/blank#} We can use both sides of every piece of paper, especially when we are making notes. We can choose drinks in bottles instead of those in paper packets. We can also use cotton handkerchiefs and not paper ones. When we go shopping, we can use fewer paper bags. If the shop assistant does give us a paper bag, we can save it and reuse it later.

    {#blank#}5{#/blank#} If we all think carefully, we can help protect trees. But we should do it now, before it is too late.

    Tokyo may be one of those places that you love and hate at the same time. In Tokyo, there are always too many people in the places where you want to go. There are also too many cars. Tokyo drivers often spend a long time in the busy street, just like drivers in London, Paris and New York.

    Tokyo also has a lot of people on foot, and sometimes it is really difficult to walk in the street. The worst time in the street is at 11：30 at night. That is because the nightclubs are closing at that time and everybody wants to go home then. There are more than 30,000 nightclubs in Tokyo, and usually none of them is empty at night.

    During the day, most people go to work by train. Six million train tickets are sold, every year in Tokyo. At most stations, trains arrive every two or three minutes, but at certain hours they are not enough at all. Although trains are always crowded, they are very good in many ways. They always leave and arrive on time. In London trains, you may see everybody reading a newspaper. But in Tokyo trains, everybody seems to be sleepy, no matter whether his journey is long or short. If you stand outside the station for five minutes, there will be three fire engineer going past you. They are on the way to one of the fires that Tokyo has every day. Tokyo has so many surprises that none of them can really surprise me now.

    Don't be too surprised if you see a car going down the road without a driver in Beijing these days. {#blank#}1{#/blank#}Last month, Baidu began to test its self-driving cars on open roads in Beijing.

    {#blank#}2{#/blank#}Since then, companies like Tesla, Uber and Baidu have been working to produce and test their own self—driving cars.

    Self-driving cars are safer than regular cars. {#blank#}3{#/blank#}They can remove the stress of driving and allow disabled or blind people to get around more easily.

    {#blank#}4{#/blank#}In one test, researchers pointed a laser pointer (激光棒) at the car's sensors (传感器) while it was moving. The car mistakenly thought that the laser beam was in its way and slowed down or changed the direction.

    The software that is used to direct the cars may not be safe enough. {#blank#}5{#/blank#}When we use our computers or smartphones, they sometimes crash (崩溃) without any reason. But if this happened to a self-driving car, the result could be deadly. Improvements to the software could be a solution to this problem.