Haiyan is 7 years old. Her parents gave her an iPad as a gift for her birthday. A month later，her eyesight（视力）dropped to 300 degrees. This is serious for such a young child.

    Many children in China are facing the same problem: iPad using is bringing problems to their eyesight. The problem is so common that newspapers even call the iPad the "No. 1 killer of children's eyesight!"

    "There are about 30 shortsighted children coming every day, "said Hu Dali, an eye doctor at Guiyang Aier Eye Hospital. "Half of those children have poor eyesight because they have played with phones and iPads for too long. "

    Doctors and scientists say children's vision（视觉）is not yet fully developed and their eyes get tired more easily. The screen of an iPad uses very bright（明亮的）LED backlight. If children look at an iPad screen for a long time, their eyes do not have time to rest. This will make their eyesight worse over time.

    Doctors advise that users should hold their iPads between 40-60 centimeters（厘米）away from them. The brightness of the screen should be comfortable for children. Parents should also stop their children from using an iPad for more than one hour every day.

    Young children don't have the skills or knowledge to stay safe in heavy traffic. The following tips (忠告) will be helpful for you to keep your children safe in heavy traffic. {#blank#}1{#/blank#} As parents, make sure that you always set good examples. Your children will follow you and think it's OK to do like you. Teach your children to pay attention to traffic lights {#blank#}2{#/blank#} This helps them understand when it's safe to cross. Make sure that you walk between your children and the traffic, and hold their hands all the time.

    {#blank#}3{#/blank#} you can start to tell them the importance of traffic knowledge. Let them start to understand the reasons why they need to be so careful. Talk with them about road signs and traffic rules.

    Ask your children to play in a safe place. Never let them ride bikes on the road without an adult present at rush hour.

    The most important thing you can do is {#blank#}4{#/blank#} so parents encourage them to follow traffic rules. {#blank#}5{#/blank#} they'll volunteer to obey them. In this way, they'll be careful enough to keep themselves away from danger.

    In life, there will always be some people or things that deeply touch you, or even change some of your ideas.

    On my way to school, I always see some people w{#blank#}1{#/blank#} in orange color and sweeping the street. They are city cleaners. People always d{#blank#}2{#/blank#} them as beauticians of the city. However, their work is really hard!

    Last week, our school carried out a social practice activity. I f{#blank#}3{#/blank#} a sanitation (环卫) worker Aunt Hu to experience. As we walked, we w{#blank#}4{#/blank#}. Aunt Hu went to clean up the rubbish when she saw it. I also c{#blank#}5{#/blank#} some leaves and waste paper into a plastic bag. After five minutes, I felt a little tired. It was very hot. How I wanted to find a cool place to have a rest! But Aunt Hu didn't mean to stop even though there was much sweat (汗) p{#blank#}6{#/blank#} over her face. Just at this time, a banana peel fell on the ground. I looked up and saw that it was t{#blank#}7{#/blank#} by a fashionable girl! I was very angry, but Aunt Hu picked it up silently and put it in the dustbin. At this moment, I was touched d{#blank#}8{#/blank#}. She left the dirt and tiredness to herself and the tidiness to us, but the girl turned a blind eye to her job!

    City cleaners are worth our high regard. Thanks to them, the public environment has become clean and c{#blank#}9{#/blank#}. The news reports how the public respects the touching news of these lovely people. We are glad to see the public's a{#blank#}10{#/blank#} to the little people.

    Laughter is natural for people. We start to laugh at about four months of age. We start to laugh even 1 we start to speak.

    Laughter connects us with others. We laugh more when we are with other people. It's difficult to pretend to laugh. Laughter is 2. When people pretend to laugh, most people know it's not real.

    When do people laugh?

    Only 10 to 20 percent of laughter is about something 3. Most laughter is about being friendly with other people. Most laughter says, "I don't want to 4 with you. I want to be friendly with you." This kind of laughter brings people together.

    We often laugh when we feel nervous. In movies, there is often a joke at an exciting moment when everyone feels nervous. It is usually a(n) 5 joke, but we laugh a lot. Our laughter helps us 6.

    Why doesn't everyone laugh at the same joke?

    Not everyone has the same sense of 7. Some people think a joke is funny, but other people don't think so. People have different ideas about what is funny.

    Our idea of what is funny changes with 8. For young children, the world is new. They are interested in many things, so they laugh 9. Teenagers often laugh to protect themselves. Adults laugh at themselves and other people with similar problems. They laugh at things that give them stress. Our 10 for laughter change gradually.

Imagine （想象） walking into a movie theater without being greeted by the smell of popcorn. It's hard to believe, isn't it? For many people, popcorn goes hand in hand with movies. They can't have one without the other. But 1  did this happen?

The 2  between the two is younger than you may think. In the mid-1800s, popcorn was already a popular snack in America. Vendors sold it on the 3  . People, especially kids, loved this street food. In the early 1900s, vendors started to sell popcorn 4  movie theaters.

However, theater owners didn't like popcorn. They believed it would make the experience of watching a movie 5  enjoyable. Eating it would make too much noise during the silent movies.

Later, when movies added sound, the 6  noise problem went away. More and more people went to the movies. Some of them even secretly（秘密地） took popcorn into the theaters. Later, more movie theaters 7  . Some of them agreed people to eat popcorn while they were watching movies.

In the 1930s, the theater owners found that people didn't need to buy popcorn from street vendors. Because popcorn was 8  to make, they could make and sell it themselves. They did that and the smell of popcorn drew more people to their theaters. The 9  made a lot of money, and people enjoyed themselves at the movies.

Today, popcorn is still an important part of the movie-going experience. Roles, a man who once ate three bags of popcorn, said, "People come to theaters sometimes just for the 10 . They don't even care what is playing!"