On a summer day in 1948, a Swiss (瑞士的) man named George de Mestral took his dog for a walk in the mountains. After they came home, George discovered that he and his dog were both covered with burrs (带芒刺的小果实).
As an engineer, George naturally began to wonder how exactly the burrs stuck to his dog and his clothes. Then he paid careful attention to looking at them under a microscope (显微镜). He found that the burrs had very tiny hooks (钩子), which allowed them to catch on to things like clothes. George realized that he could use this finding to create a new way to fasten (扣紧) things.
As so often, it is a very long journey from the first idea to the final product. It was easy to find materials that could stick together, but finding materials that would continue to do so after years of use was not easy. George tested a very large number of different materials and production methods. After years of research and work, he invented what is known today as Velcro (魔术贴). In 1955 George started Velcro Industries to turn his idea into a product. In a few years, the product became popular around the world.
Today Velcro is used everywhere. It’s used in backpacks, jackets, wallets, children’s toys, etc. It even turns up in places you wouldn’t expect. For example, Velcro has been used by NASA for astronauts’ suits. The product was also used to hold the heart together during the very first artificial heart transplant (人工心脏移植).
Complete the summary of the passage above with one word for each blank.George de Mestral was an engineer from Switzerland. One day in 1948, after coming back from the mountains, he found some burrs on his clothes and his dog. Then he It was hard to find |
Long ago, as people got older, there was something wrong with their teeth and it would be very painful. To avoid toothache, they had their teeth pulled out.
Later people learned that cleaning their teeth was important, but they didn't have toothpaste (牙膏) at that time. They used lemon juice (柠檬汁), salt or other things to clean their teeth.
About 100 years ago someone finally created a kind of cream to clean teeth. Not long after that, the toothpaste tube (管子) was invented, so people could press the toothpaste right onto the toothbrush! Tooth brushing became popular during the World War I. The army gave brushes and toothpaste to all the soldiers, and they learned to brush teeth twice a day. At that time toothpaste tubes were made of metal. Today they're made of soft plastic and are much easier to use!
Today there are plenty of toothpaste choices: lots of colors and tastes to choose from, and some kinds of toothpaste are made just for children. When you're choosing a kind of toothpaste, make sure it has fluoride (氟化物). Fluoride makes your teeth strong and healthy.
Great Invention—Toothpaste | |
| Why people had their teeth | To avoid toothache |
| What people used to clean their teeth before toothpaste was invented | Lemon juice, salt or other |
| When toothpaste was created | About one |
| What disadvantage toothpaste tubes made of metal have | They are much |
| What kind of toothpaste you must | Fluoride toothpaste |
根据短文内容完成表格，每空一词。
During the ongoing COVID-19 crisis, some city buses and trains have run empty, while others have been crowded.
To solve this and other problems during the pandemic, some cities are turning to programs called microtransit (微交通)—imagine Uber and a city bus had a baby to offer basic service, like moving the elder to drug stores or nurses to hospitals.
Some microtransit companies made a function called contact tracing (接触者追踪). The method makes use of smartphones. Users who fall ill report it through an app on their phones. Then it sends notices to anyone they had gotten close with.
Many countries around the world are working on contact tracing app. China has used contact tracing since February. Chinas contact tracing system lets the nation know the locations of the phones running the app. Chinese citizens also get QR codes to see if they are allowed to be in public. Gradually, the method stopped the spread of the disease. In March, Singapores government released one that uses Bluetooth transmitters in peoples phones. Australia released its own app in April.
Microtransit could still be valuable as social distancing ends and more people begin to move around cities. It is easier for people to use traditional public transit. It could also be used in areas with little public transit service and long distances between stops.
Because of COVID﹣19, there is something wrong with some cities public transportation. So they thought of a |
Just as email has changed the way we write to each other, e-books are changing the way we read. An e-book is known as an electronic book, and it is simply a print book in an electronic way.
There are many advantages of e-books. As we all know, we can easily download new e-books from the Internet. It is much easier and quicker to search for passage now, and we can also write notes in an e-book. What is more, they save a lot of paper.
Every coin has two sides, e-books also have some disadvantages as well. For example, e-book readers are still more expensive than paper books, so not all people can afford them. Furthermore, e-Book screens may cause eye strain if you keep reading for a long time.
However, with the rapid development of electronic technology, reading e-books will become cheaper and cheaper. A lot of people think there will be more e-books than paper in the near future.
| Advantages of e-books | Disadvantages of e-books |
| It is easy for us to | They are much |
| It is more convenient and quicker passages. | If we keep It may cause our eye strain. |
| A lot of paper can be |
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