We need animals. Every animal has its place in the balance(平衡) of nature. We should try to help save the animals.

    Some people think zoos are good places. The zoos give the animals the comfortable and safe living places. If the animals get hurt or ill, people will take care of them. The zoo is a good place to know the rules in the wild world. We can be much closer to nature. We can know more about the animals in the zoos by watching, listening even smelling instead of just looking at the pictures in books.

    Some people don't think animals feel happy in the zoos. Animals like pandas, wolves and bears usually live in the wild. They play and find food by themselves. They are free and happy in the wild. If they are in the zoos, food is enough and rooms are comfortable. They do not need to do their best to find food to eat or places to stay in. They just walk around, sleep day and night, but they are not free at all.

    I think we should build national parks as wild life nature reserves to protect animals. If we do nothing, animals will get fewer and fewer.

    You must think a computer is the best thing in the world, right? You must think it works at a super speed and can do everything? Well, it's not! In fact, the brain is much more powerful than any super computer! Think about when a glass is just about to fall off the table. Your brain controls everything that you need to do to save that glass from falling. First your eyes check out what's going on, then tell your brain, and your brain decides how quickly you need to react(反应), and then your muscles(肌肉) go into action. That is just from your brain. No computer could ever come close to that!

    The brain weighs just 3 pounds, but it controls everything you do from thinking, learning, feeling even to breathing and your heart beating. Even though the brain is just 2% of your body weight, it uses around 20% of all your energy in your body. That is a lot for such a small organ(器官). There are about 100 billion tiny, tiny little cells(细胞) in your brain. There are so many that it would take you over 3,000 years to count them all!

    Your brain stops growing when you're 18, but it actually keeps on developing and learning new things. So your parents are really super smart! You won't be able to fool them! Believe it or not, your brain NEVER stops working. Even during sleeping, the brain works for long-term memory establishment(建立). It is realized that the brain is the second organ in the body as the heart that never stops during human lives.

    So everyone should be proud of such a gift of nature.

    As space science develops, man has learned more and more about space. Space is not only amazing but also dangerous. While working in space, spacemen are facing danger as well as success.

    Scientists have found out that the radiation（辐射）is the greatest danger to spacemen in space. When spacemen are working in space, they are in danger of the radiation from the sun and other stars, which is bad for their health. The harm of the radiation won't be found until their children even grandchildren are born. Some special medicine may work a little, but no really effective medicine has been found so far.

    Space rubbish is also thought to be a great danger to spacemen. It's reported that there were 9,000 man-made things flying in space. About 30% of these are satellites, 10% are spaceships, and the rest are space rubbish. An explosion（爆炸）in space in 1999 made a cloud of 300,000 fragments, each at least 4mm in size. A small piece of these even knocked a spaceship window and caused some damage（损坏）.

    Scientists are watching and reporting any possible danger all the time. They are working to deal with space rubbish. Although space is really dangerous, it interests many people on the earth. In the near future, it may be possible for people to spend a few days in a space hotel. We may even choose to leave the earth and live in space in a few years. So we should do something to help improve the space environment.

    Started in 1636, Harvard University is the oldest of all the colleges and universities in the United States. {#blank#}1{#/blank#}

    In the early years, these schools were much alike. Only young men went to college. {#blank#}2{#/blank#} Little was known about science then, and one kind of school could teach everything that was known about the world. When the students graduated, most of them became ministers or teachers.

    In 1782, Harvard started a medical school for young men who wanted to become doctors. Later, lawyers could receive their training in Harvard's law school. {#blank#}3{#/blank#} Soon it began teaching American history.

    As knowledge increased, Harvard and other colleges began to teach many new subjects. {#blank#}4{#/blank#}

    Today, there are many different kinds of colleges and universities. {#blank#}5{#/blank#} There's so much to learn that one kind of school can't offer it all.

A. In 1825. besides Latin and Greek, Harvard began teaching modern languages, such as French and German.

B. Most of them are made up of smaller schools

C. Yale, Princeton and Columbia were opened soon after Harvard

D Students were allowed to choose the subjects that interested them

E. All the students studied the same subjects, and everyone learned Latin, Greek and Hebrew

In the eyes of many foreigners, Chinese are the best hosts and the worst guests in the world. They're not really bad guests but because the guest-host relationship in China is much different than in some Western countries it appears they are not nice guests. And Western guests sometimes look rude in the eyes of Chinese guests.  

　　In China guests are almost like gods. Whenever I enter a Chinese person's home there is always fruit on the table for me and someone is quick to bring me a cup of tea or water. In the West generally the guest is not a god. Acting according to the host's way of doing things is usual behaviour for a guest. 

　　My wife's mother is a very kind elderly Chinese lady who doesn't smoke. When I see some of her guests smoking in her house, as a non-smoker I feel unhappy. Usually I want to stop them directly but I must realize that she must not do that. In most North America homes if you are a guest and the hosts are not smokers, you should not smoke in their house. At the very least you could ask "Is it OK if I smoke?" But don't be surprised if they say "No, you can't smoke." In our culture if you smoke in their home you are a bad guest, but if they don't allow you to smoke in their house they are not a rude guest.

　　Guests in China also have special habits. Some Western people may not adapt to these habits very soon. Thankfully my wife is Chinese so whenever we visit a Chinese family she tells me to buy them a gift. However giving a gift to a host is not always necessary in my country. So if you invite international guests to your home don't be too surprised if they don't bring you a gift. 

　　In China you probably won't need to change the guest-host relationship very much because you will probably only be the host and Chinese are naturally very good hosts. If Western hosts invite you to their house, try not to be too surprised if their style of treating you is not what you have expected.

There is a 3D-printed library in our community (社区) . It was printed out in three {#blank#}1{#/blank#}. This library is special, just like a bird flying in the sky. There are different {#blank#}2{#/blank#} of books in this library. You can spend time {#blank#}3{#/blank#} books there. You can also choose some books you like from there {#blank#}4{#/blank#} return them three days later. There is a special box in front of the library. You can put some old books {#blank#}5{#/blank#} the box. Anyone can open the box and {#blank#}6{#/blank#} some books to read. These books can take away for {#blank#}7{#/blank#}. In return (作为回报), you need to put some old books in the box. It quickly became {#blank#}8{#/blank#} around the community. The box give people free books to read and make neighbors {#blank#}9{#/blank#}. Now this library has {#blank#}10{#/blank#} a hot topic online.