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Read the article. Match the title to each paragraph. (Đọc bài văn. Nối tiêu đề đúng với mỗi đoạn văn) a. A twenty-first century problem b. The problem of light and screens c. Why do we need to sleep? 1. Why do we steep? One thing we do know is that it's good for our physical and mental health Physically, sleep helps prevent sickness and keeps our body healthy. Mentally, we study and work better when we sleep for about eight hours the previous night. In this country lack of sleep is becoming a big problem. The average American sleeps less than seven hours a night-that's two hours loss than a century ago. Our modern 24-hour-day lifestyle means that more and more of us are working at different times of the day-and night. We often stay up late into the night, and some of us even work all night and sloop during the day. This is a problem because our body's natural clock is connected with the movement of the sun. If we don't sleep at night for long periods, it can be bad for our health. But perhaps the biggest problem comes from electric lights and screens. Modern cities use bright LED lights through the night, which changes the way we sleep. In addition, the screens of our computers, tablets, and smartphones all send out blue light. The bluer and brighter the light, the more difficult it is to get tired and go to sleep. As a result, some medical experts suggest that we shouldn't watch more than two hours of television per day, and that we should stop looking at screens (including phones) one hour before we go to bed But how many of us will take this advice?

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Read the following passage and mark the letter A, B, C, or D to indicate the correct answer to each of the questions. Try to imagine what life would be like if there were no electric lights, no television, or no cars. What if you had no running water to take a shower and no refrigerator to keep your food cold? Life would be tough without these great inventions. Since ancient times, people have been inventing new machines, materials, and ways of doing things. The people who come up with new things are called inventors. Sometimes an inventor makes an invention to solve a problem. Sometimes an inventor discovers something new by accident. Everyone probably has his or her favorite inventions. One great invention was the printing press. A German named Johannes Gutenberg in the 1400s invented a press that made it easy to print books. Books became much more common after the invention of the printing press. The books helped other inventors make new things. The invention of the steam engine around 1700 led to the Industrial Revolution. Inventors made many new machines that were powered by steam engines. They invented locomotives, steamboats, and all kinds of factory machines. Another great invention, the internal combustion engine, led to the invention of automobiles in the late 1800s. Inventors made better and better internal combustion engines. These are the engines we use today in cars, trucks, buses, and airplanes. The discovery of electricity led to many wonderful inventions. Many scientists studied electricity. An American inventor named Thomas A. Edison invented the electric lamp, phonograph, and other things that ran on electricity in the late 1800s. New things are invented today faster than ever before. Inventors are making new kitchen appliances, toys, computers, video games, telephones, and all kinds of other things.   The passage mainly ____.

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