“Twinkle Twinkle Little Star” is a popular song for children. But have you ever wondered why the stars twinkle? I’m afraid many adults don’t understand this question, let’s unlock the mystery of the stars!
When we look up to the sky on a clear, dark night, our eyes can see about 6,000 stars in the sky. Some stars look like they are always twinkling and winkling. They are very beautiful. In fact, most of the stars are shining with a steady (稳定的) light. Not all stars twinkle. The stars that twinkle are generally stars. In addition to the Sun, the nearest star to the Earth, the neighboring star (比邻星), is also more than 4 light years away from Earth. Because the distance is too far, the stars we see are only a small point. Also, from the distant star travels a long way through the atmosphere (大气) down to us on Earth. At the same time, air is moving in the atmosphere of Earth. The movement of air causes the starlight to get slightly bent. To our eyes, this makes the star to twinkle. You will notice that stars closer to the horizon appear to twinkle more than other stars. This is because there is more atmosphere between you and a star near the horizon. However, there is no atmosphere in space to make the stars seem to twinkle. That’s why the Hubble telescope (哈勃望远镜), which is in space, can take such clear pictures of other galaxies (星系).
Go out tonight and take a look at the stars twinkling in the sky!
1. On a clear, dark night, our eyes can see _________ stars in the sky.A.less than 6,000 | B.around 6,000 | C.more than 6,000 | D.Not mentioned in the article |
A.bright | B.colourful | C.fixed | D.flashing |
A.The movement of air in the atmosphere of Earth. |
B.Air on Earth. |
C.The long distance between stars and Earth. |
D.The movement of stars. |
A.Because stars twinkle in space. | B.Because air is not moving in space. |
C.Because the telescope is close to stars. | D.Because there is no atmosphere in space. |
A.Why are many stars so dim at night? | B.Which song do children like best? |
C.How to observe the stars from Earth? | D.What do stars look like? |
相似题推荐
【推荐1】Do stars only appear at night? The answer is no. Venus(金星)is the one and only star that can be seen in the daytime. It shone at its brightest in the night sky on February 17, 2017.
Venus is the second planet in order from the sun. It is the second brightest natural object(物体), behind the moon, in the night sky. Why is it so bright? First of all, Venus is the closest planet to the earth. It is also covered by highly reflective(反射的)clouds, which can reflect about 70 percent of the sunlight shining it, almost twice as much as the earth doe.
Some people called 2017 the year of Venus, because the planet was at its brightest twice in the year. Venus gets brighter when it goes further away from the sun, and nearer to the earth. The brightest moment happened once in February, and happened again during daylight on April 30th.
Venus is closer to the earth than Mars and it’s closer to the earth in size. Isn’t it a better choice for human exploration(探索)than Mars? However, with a temperature of about 465℃ on the surface, Venus is the hottest planet in our solar system! So people haven’t explored Venus yet. But scientists never give up. Recently, a team of NASA and Russian scientists created a new computer equipment that can stand temperatures of 480℃. It can work under Venus-like conditions for almost 22 days. The next step, according to the scientists, is to send a probe(探测器)to Venus by 2025.
1. Which of the following is not true about Venus?A.It is the second planet in order from the sun. | B.It once shone at its brightest in the night sky. |
C.It is the one and only star that can be seen in daytime. | D.It is the second brightest natural object behind the earth. |
a. it can reflect about 70 percent of the sunlight
b. it is covered by highly reflective clouds
c. It is the closest planet to the earth
A.a, b | B.b , c | C.a, c | D.a, b, c |
A.Because it’s closer to the sun. | B.Because it’s closer to the earth in size. |
C.Because it’s the hottest planet in solar system. | D.Because it’s closer to the earth than Mars. |
A.is a useful probe |
B.can stand temperatures above 480℃ |
C.can work under Venus-like conditions for about 22 days |
D.is created only by Russian scientists |
A.In a science magazine. | B.In a travel guide. | C.In a novel. | D.In a short story. |
Do you know anything about the Moon?
Scientists have told us so much about the Moon.
The Moon is an unfriendly place.
But from the Moon, you can see our beautiful Earth. It is shining more brightly than the other stars in the dark.
A.There is no air or water. |
B.How much do you know about it? |
C.The Moon is also a very quiet world. |
D.You can take some photos with your camera. |
E.It’s meaningless for us to have the idea of going to the Moon. |
F.When the Sun shines in the day, the temperature is very high. |
G.It’s hard for us to live on the Moon. |
【推荐3】A question has made the public think a lot for more than a century: Whether(是否) there is life on Mars.
A British spaceship and Europe’s Mars spaceship plan to land on Mars or enter the orbit(轨道) around it. One of the NASA’s spaceships is going to land on January 3, and the other is going to land on the opposite side of Mars on January 24.
Since 1960, over twenty spaceships sent to Mars have failed. Most were lost when they started flying up or landing because those were the most difficult time of any flights.
Scientists wanted to find out whether there was water on Mars. In October, a team of scientists reported that Mars was a dry wasteland(荒地). But weeks later, a second team reported differently that they had found some marks(痕迹). They showed clearly that they were made by the rivers. Such marks told us that Mars was a warmer place billions of years ago—just as life first appeared on Earth. Scientists at once asked the following questions: If it was true, what happened on Mars? Then what about the earth?
Maybe one day, in the near future, human beings will land on Mars, settle on Mars, and directly look for life.
1. What are people talking about for more than a century?A.When Mars came into being. | B.Whether there is life on Mars. |
C.Whether people can live on Mars. | D.How people can fly to Mars. |
A.will land on the different sides of Mars | B.will land on the same day |
C.will enter the orbit around Mars | D.will land with a man |
A.A travel guide. | B.A film magazine. | C.A music website. | D.A science book. |
【推荐1】In the 13th century. Marco Polo the world known Italian travelled saw many wonderful things in China. One of the things he discovered was money made of paper. People in the West did not have such kind of money until the I5th century. However the Chinese began to use it in the 7th century
Paper was invented by a Chinese man called Cai Lun almost 2,000 years ago. But it was not made in Europe until the year I 100. Four hundred years later, a German discovered that he could make the best paper from trees. After that countries rich in forests, such as Canada Sweden. America. Finland became the most important ones in paper making
Paper can be used in many ways. The common uses include newspapers magazines and books. But do you know that paper can be used for keeping warm? In Finland. the farmers wear paper boots to keep their feet warm in the snow. And even houses can be insulated(使绝缘)from heat or cold with paper.
However. we have to understand that paper still comes from trees now. If we keep on wasting so much paper, there will not be any trees left on the earth some day in the near future. Every day people throw away about 2, 800 tons of paper in our city. It takes 17 trees to make one ton of paper. This means that we are cutting down nearly 48.000 trees every day. The fact is that it takes more than 10 years for a tree to grow.
So we must start saving paper right now. We can use both sides of every piece of paper. We can make useful things out of used paper. We can use china cups instead of paper ones. When shopping, we can use fewer paper bags and reuse them if we have some
In short, we should keep a balance (平衡)between using paper and protecting trees, and do it now before it is too late.
1. When did the Chinese begin to use paper money?A.In the 5th centurn | B.In the 6th century |
C.In the 7th centurn | D.In the 15th century |
A.Because it was a large country | B.Because it had lots of forests |
C.Because it was a very rich country | D.Because the inventor was from Canada |
A.making beds | B.reducing waste |
C.making umbrellas | D.keeping warm |
A.10 | B.17. | C.2,800 | D.48,000 |
A.how paper boots are made | B.how paper was invented |
C.how we can save paper | D.how we can make useful things |
【推荐2】
Have you ever heard that it’s impossible to fold a piece of paper more than seven times? Actually, it is just a popular myth.
The myth refers to folding a piece of paper in half many times in any direction. The paper is folded in half. Try it for yourself with a piece of notebook paper. The first few folds are easy. But when you make the fifth and sixth folds, you’ll notice that it’s increasingly hard to fold the paper. Why does it happen? That’s because the number of the layers (层) of paper doubles with each fold. For example, after the sixth fold, you’re left with 64 layers of paper. If you have strong hands, you may be able to make that seventh fold. If you start with a piece of paper that is 0.01 centimeters thick, it’ll be as thick as a notebook after seven folds. And it would seem impossible to make more folds. At this point, you may be thinking that the paper-folding myth doesn’t sound much like a myth.
However, in 2002, a high school student named Britney Gallivan proved the idea wrong. Britney successfully folded a 1.20-meter-long roll of toilet paper 12 times (note that she used single-direction folding). She also developed a math rule. This is convenient. It allows you to find out the maximum (最大的) number of possible folds based on paper thickness, paper length, and direction of folding.
Since Britney’s success, many people have managed to fold a single piece of paper more than 7 times. Students even folded a piece of toilet paper a total of thirteen times. The toilet paper they used was about 4,000 meters long!
1. How thick is the notebook mentioned in the second paragraph?A.0.01 centimeters. | B.0.07 centimeters. | C.0.64 centimeters. | D.1.28 centimeters. |
A.Absurdity. | B.Truth. | C.Imagination. | D.Fiction. |
A.Man doesn’t have a greater enemy than himself. |
B.A man becomes smart by asking questions. |
C.Knowledge is the most valuable of all things. |
D.Things that seem impossible may be achievable. |
A. | B. | C. | D. |
A.Rule of Paper-Folding | B.A Paper-Folding |
C.The Paper-Folding Myth | D.The Art of Paper-Folding |
【推荐3】We use our smart phones to carry out many tasks every day. Many of us become so reliant (依赖的) on them. However, it is bad for our eyes and health to spend too much time on phones.
A study shows that smart phone owners usually start to use their phones early in the morning. They check personal emails and WeChat (微信). And before they get out of bed, many people often check the weather, read the news, and send a message or two to friends. After getting up, they often take photos of food, and even whatever they can see with their phones. They share their photos with their friends. The research finds that users pick up their phones over 1,500 times to do different tasks in an average (平均的) week. And the smart phone users are on their phones for three hours and sixteen minutes a day. That is to say, people use their phones for almost one full day each week.
Using phones can take much time and it’s also bad for our health. Many people stay up late to play phones. And mobile phones can influence (影响) our sleep. Without using the phones, many people may feel sad. Many owners also find they use their phones without realizing they’re doing so.
How do you think people use their phones too much?
1. What does the underlined word “check” in Paragraph 2 mean?A.Look over. | B.Close. | C.Hear. | D.Find out. |
A.checking weather | B.sending messages | C.reading news | D.taking photos |
A.In a newspaper. | B.In a travel magazine. | C.In a storybook. | D.In a history book. |
A.The ways people use their smart phones. |
B.The history of smart phones. |
C.The reason that people love smart phones. |
D.The influences that smart phones have on people. |
Do you believe stones can move by themselves? There are some stones that can move in Death Valley (死亡谷) of the USA. Many of the stones are small, but a few of them are big. The biggest stone weighs about 350 kg.
The stones only move at night. Nobody has seen them moving, but now scientists know why the stones can move. The answer is the wind. When the wind comes from the west (西), the stones move to the east (东). When the wind is from the south, they always move to the north (北). But how can the wind move the heavy stones?
Death Valley is one of the hottest places in the world, but it can be very cold at night. Sometimes, there are even storms at night. Rain falls, and the wind is strong and cold. The water on the ground turns into ice (冰) easily. Then the strong wind can move the stones along the flat (平的) ground. In the morning, the sun comes up and dries the ground. Then people can find the stones move from one place to another in the daytime.
1. Death Valley in the USA is famous for ________.A.the storms | B.the wind | C.moving stones |
A.the southwest (西南) | B.the southeast (东南) | C.the northeast (东北) |
A.Nobody has seen the stones moving. | B.Many tourists go to visit Death Valley every day. | C.The strong wind can move the stones along the flat ground. |
A.The Hottest Place in the World | B.The Weather of the USA | C.Moving Stones in Death Valley |
【推荐2】Hello! My name is David. I live with my parents in China. My mother, Lily, is from(来自) Chongqing, and my father is from Chengdu. His name is Paul. My mom likes Chongqing very much. She says if(如果) you want to eat delicious(美味的) food, you can go to Ciqikou. If you want to go shopping, you can go to Jiefangbei. If you want to see the beautiful night view(夜景), you can go to Laifushi. But my father says it's more relaxing(更放松) to go to Chengdu. You can go to Kuanzhai Alley(宽窄巷子) to eat delicious food. You can see many pandas in Chengdu. You can go shopping in Chunxi Road, too. I think my parents are fun. I like Chongqing, and I like Chengdu, too.
1. David is Paul's __________.A.brother | B.father | C.son | D.mother |
A.eat delicious (美味的) food | B.go shopping |
C.see many pandas | D.see the beautiful night view (夜景) |
A.Ciqikou | B.Jiefangbei | C.Chunxi road | D.Kuanzhai Alley |
A.You can go to Laifushi to see the beautiful night view. |
B.You can see many pandas in Chongqing |
C.You can go shopping in Jiefangbei and Chunxi Road. |
D.The writer(作者) likes Chongqing and Chengdu ,too. |
【推荐3】When I was about 10, there were lots of us bored, bookish children in the 1970s. Television was largely rubbish, and our parents’ bookshelves were what was left. I thought of this when I heard author Claire Tomalin complain that children are growing up without the skills to read classic works of English literature, such as Charles Dickens and that they are not being taught to have the lengthy attention spans (时段) necessary for his texts. She blames this attention shortfall on the terrible television programmes.
It is true that children have never had more entertainment (娱乐) to choose from than today. And it is probably true that this generation’s attention span is shorter; my children have dismissed as “too slow” or “boring” most of the childhood books I saved for them. I was quite upset about this until I reread some. It is not just entertainment that moves at a faster rate. The world does, too. And, frankly, Dickens is dense, and hard work, as are many writers of that period.
Another fact is that not many children of my generation read Dickens for pleasure either. It took me years to come to Great Expectations and The Pickwick Papers, and then it was only post-university when I became independently hungry for knowledge.
Dickens might be one of the greatest creators of characters in English, as Tomalin says, but today’s children see Greg Heffley’s nature in The Wimpy Kid of Jeff Kinney’s novels. And they are so interested in the resourceful Baudelaire children in Lemony Snicket’s A Series of Unfortunate Events. They can recognize the adolescent difficult situation of Harry Potter.
You can’t insist that childhood tastes not change for a long time. My mother encouraged me to read anything on the basis that all reading was valuable, and would act as a gateway to more challenging works later on. In turn, I believe that my children will come to the classics when they’re ready. Until then, I’ll take comfort from the fact that the 1969 classic The Very Hungry Caterpillar is still the most-read children’s book in Britain. It has underdeveloped characterization, yes, and the vocabulary is limited. But as a starter to give children an appetite (食欲) for reading, it is priceless.
1. What is important for children reading Dickens according to Claire Tomalin?A.Vocabulary. | B.Patience. | C.Knowledge. | D.Taste. |
A.They are difficult to understand. |
B.Their vocabulary is old and limited. |
C.They are the entrance to other literature works. |
D.Their characters are better created than today’s works. |
A.understandable | B.worrying | C.disappointing | D.interesting |
A.Attention span. | B.Classic works. | C.Reading skills. | D.Children’s reading. |