In the beginning, the computer was as large as a room. This worried the designers. As time went by, it became smaller and smaller. With artificial intelligence, it was getting        (smart) and quicker. In the early 1960s, computers        (connect) by a network, which enabled their users to share information with others. Since the 1970s, computers        (become) very important in communication, finance and trade.

    Mr. Black offered his advice on        (choose) a good school for Paul. The one at Caen was generally considered to be the best. So Paul decided to go to Caen. He said his goodbyes        (brave), for he was quite pleased that he was going to live in a place        he would have some friends of his own. His mom was unhappy, however, she had to accept it because she knew that he must have a good education. Paul's sister quickly got used to being on her own, but she        (find) the house very quiet without him.

    Bicycles,        used to be a major means of transportation, are becoming popular again. New York City, together with London, Paris, Hangzhou and many other        (city) throughout the world, gets bike-sharing systems of their very own. More and more people are considering using bikes        a replacement for cars, and how to improve bike-friendly crossroads is also under discussion.

    When Marco Polo was 17 years old, he travelled        Europe and Asia with his father, who wanted to do trade with the Chinese. And        they arrived in Beijing.

    Marco was amazed by how beautiful and powerful China was. He was impressed by Beijing and the Emperor's palace. He was surprised to see Chinese people using paper money in the markets because he could not understand how people could pay for food and valuable things with paper! He was also        by the black stones people used to burn for fuel. The black stones were coal, but Marco had never seen it before.

    Not long after his return to Italy, a local war       . During the war, he was caught by the enemy and put into prison. Another prisoner, who was an author, took        while Marco told all his stories about China and wrote the stories in a book called The Description of the World.

Finding Home

    "I hate New Orleans! I wanna go home!" I 1 to my mother as we moved boxes. 2 , going home was not easy because my home was 1, 100 miles away.

    I was born and 3 in northern Virginia. Virginia was my home, and I never expected that to 4. In 2014, my family experienced a tragedy (悲剧), so my parents decided to move to my mom's hometown of New Orleans.

    Only three months after my parents made the 5 to move, I found myself moving boxes into our new house. My announcement to my mother that I 6 the new environment was partly motivated by how hot it was, but it was mostly due to the fact that I felt like my entire life had been turned upside down. 1,100 miles away from everyone and everything I had ever known, I was 7. To make matters worse, I was starting high school in two weeks Beginning high school is a scary 8 on its own.

    I spent my first few months in New Orleans, 9 wanting to go home to Virginia. But after a few months of missing home, I 10 that I had a choice. I could continue thinking about how much I missed my old home, 11 I could start trying to build a new home right here. I chose the latter.

    As soon as I stopped giving all my 12 to how much I missed Virginia, I was able to begin accepting the love that people were already giving me. I joined some clubs at school, which gave me the chance to make friends. My neighbor taught me how to cook some New Orleans food, and I found a wonderful 13 of fellow cooks and neighbors. Overall, I seized every possible opportunity to 14 myself and to rebuild my life.

    Because of my resilience (复原力) in creating a new home for myself and the 15 that people have shown to me, home is right here.

    It was May 23, 2016. Arnot, the 32-year-old mountain guide, reached the top of Everest without the use of oxygen (O₂) equipment. It was achieved after seven years, three previous attempts, and fourteen straight hours of climbing.

    After 15 minutes at the top, Arnot began her descent (下坡). Eight hours later, she reached the camp at 7, 600 meters and became the first American woman-and only the seventh woman ever—to successfully reach Mount Everest without oxygen equipment.

    "There are so many reasons for her impressive achievement, especially the physical and emotional efforts that she's put forth over the years to make this happen," says the professional climber and photographer Richards, "The mental courage that it requires is something very few people have."

    Arnot didn't start climbing until she was 19 years old. Money was tight in her family, and climbing mountains never occurred in her mind. After graduating from college, Arnot was invited by her friend to climb a mountain. "It totally changed my life, says Arnot. I always know that if you want something, you can achieve it, but knowing what you want is a whole different thing," she says. "I am athletic but not competitive. After my first climbing, I knew immediately that mountains are what I want—as that is where I felt home for the first time in my life."

    After that first climb, she devoted herself to learning how to climb and move through mountain. It was during her second trip to Everest in 2009 that she first set her sights on a no-oxygen attempt. However, while hiking into Everest Base Camp that year, she hurt her leg and wasn't able to climb without oxygen. In 2013 she nearly made it to the top, but was forced to take oxygen at 8,504 meters while helping another climber.

    When Arnot finally stood atop Everest, she called her best friend, "I reached the top and I'm not using any oxygen." Then, tears began to stream down from her eyes. So much of Arnot's life has been about pushing the limits of her abilities, and in this case, she's also pushed up against the outer limits of the human spirit.

    If you're a cycling lover, you will have to pay a lot of attention to your bicycle and maintain it well, for bicycle parts are exposed to wear and tear (磨损) over time and you have to examine the bicycle to see if there are any signs of wearing such as scratches, dents (凹陷) etc. Sometimes, a part may not work because it has exceeded its life expectancy. Sometimes, you will need to find replacement parts for it to keep up the performance of the bicycle.

    Different parts of a bicycle will wear at different rates so it is very important that you have a basic understanding about the role played by each part. One of the most important parts of the bicycle is the frame. You will need to choose a frame that lasts for a very long time. Of course, you will see some paint scratches after some time. When you're selecting a frame, you have to think about the material. Aluminium (铝) frames will not rust easily, but they have a higher chance to dent. Steel frames will be hard to dent, but you will need to make sure they get a good paint job so that they won't rust.

    Wheels also experience a lot of wear and tear and you should go for a professional seller when you want to buy wheels. There are different types of wheels that you can buy, like Zipp wheels that provide more aerodynamic efficiency (空气动力学效能). Investing in new tyres instead of going for used is a good idea because you will be able to get more use out of it. The same goes for chain as there's a higher chance of a used chain breaking. You may also experience shifting problems. However, some parts of bicycles such as pedals can be used for a long time and you can find different styles.

    Other parts that you can buy used are seats, handlebars and the stem. When you are buying handlebars, you have to see if there are any dents or if they have been bent out of shape. There shouldn't be any cracks in the seat post or the handlebars. There are many shops where you can buy parts, so you will have to check the references to see how customers respond to them before you buy anything.

    The day will come when renewable energy such as wind, solar, geothermal and others replace fossil fuels as the major source of world energy. However, most analysts insist that this day will not arrive for many decades to come—certainly well past the middle of the century. Systems of fossil fuels have already been firmly set up, and it is too costly or impractical to replace the existing systems with renewables. But there are good reasons to believe that the transition (转变) to renewables will come much faster than previously thought.

    It is hardly surprising that many experts say we will see a relatively slow transition from fossil fuels to renewables, given what is known about previous energy changes of this sort. "Energy transitions take a long time," observed Vaclav Smil of the University of Manitoba in Scientific American. It took more than 50 years for coal to replace wood as the world's leading source of energy and another 50 years for oil to replace coal; the change from fossil fuels to renewables, he argued, is not likely to come any faster.

    Under ordinary circumstances, Smil's forecast would no doubt prove accurate. But these are not ordinary times. Growing concern over climate change is leading to increasingly strict controls on CO₂ and other greenhouse gas (GHG) emissions (排放), while the development in renewables technology is lowering their price and speeding their installation.

    There are, of course, many difficulties in the effective control of carbon emissions, as demonstrated by coal companies to block the introduction of new rules by the US Environmental Protection Agency. Nevertheless, it is impossible to dismiss the progress being made at the local and international levels to promote the use of renewables. The European Union (E. U), for example, is well on the way to achieving a 20% reduction in GHG emissions from 1990 levels by 2020, along with a 20% increase in the use of renewable energy.

    The transition to renewables will be faster due to dramatic improvements in the pricing and performance of such systems. As a result of the steady increases in the efficiency of wind and solar systems, together with the savings achieved through large-scale manufacture, the price of renewables is falling globally. With prices dropping this fast, solar energy is now proving competitive with fossil fuels for generating electricity in many areas.

    The change from fossil fuels to renewable energy will not come overnight, and it will not escape many setbacks. Nevertheless, renewables are likely to replace fossil fuels as the main source of electrical power well before mid-century.

Why Do People Enjoy Extreme Sports?

    In recent years, the term extreme sports has evolved on grand scale. It can be divided into three main types: Air, Land and Water. Now you'll start wondering how they work and why people enjoy them.

    Often popular in younger-than-average crowd, the extreme sports are not organized by schools. These sports are practiced mostly on individual level, while in many cases professional coaching is also available.

    Now we tell you the secret recipe of their popularity:

    Control and Physics: The reason why people enjoy these sports is that they are normally played, exercised or practiced in free or uncontrolled environment like base jumping and sky diving. It means while traditional athletes play in controlled environment like fields and gyms, extreme athletes have to operate and display their skills in free-flowing natural environment. For this reason, the understanding of laws of physics and how to apply and use them are really crucial for success.

    Thrill: This is the single most attractive factor in people's interest in extreme sports. It makes extreme sports different from any other type of sports. The thrill one can get from extreme sports is the highest. But the athletes are fully exposed to direct danger. Thus, you have to fully understand the consequences before you decide to enjoy the thrill.

    Pushing the Limits: Extreme sports, as the name goes, is about pushing the limits. The response, nerves and the control over the un-controllable are the main reasons why people enjoy it.

    Man against Nature: As we mentioned earlier that it is about natural elements—Air, Water and Land, these games are loved because the natural elements react to human extreme. The passion of man to overcome the natural barriers is an addiction for these athletes.

    Some of the mainstream extreme sports are base jumping, bungee jumping, sky diving, gliding, extreme skiing, mountain biking, cliff diving, scuba diving and wind surfing. No matter what extreme sports you may enjoy, the No. 1 rule is to know your limits, or you'll be pushed.

⑴景点的简介；

⑵将此景点作为实践活动基地的优缺点；

⑶你对到此景点参观的建议。

注意：⑴词数不少于50。

⑵开头已给出。

提示词： the Great Wall; the Forbidden City

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