Why Do We Yawn?
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Do you yawn? There are about 20 reasons that scientists think are possible for yawning after research. They do not know exactly why yawning happens, but they do know many facts about yawning.
We know that everyone yawns in the same way. First you open your mouth slowly. Your mouth stays open for about five seconds. You take in a lot of air and then push it out. Then you quickly close your mouth. We also know that yawning is contagious. When you see someone yawn, you yawn, too.
Many people say they yawn because they are bored or tired. That might be true. People do often yawn before they sleep and after they wake up. However, we know that people also yawn when they are excited or nervous. Olympic runners, for example, scientists found that a yawn can help a warm brain cool down.
Some scientists believe that yawning makes you notice things more quickly. When you yawn, you breathe deeply. You also stretch (强化) the muscles (肌肉), mouth, and neck. Your eardrums stretch, too. Maybe this helps you to be quicker to notice things.
In some countries, people think yawning is not nice. People put their hands over their mouths to cover a yawn. In other countries, people think yawning is healthy. They think that opening the mouth very big can let good things in. When they breathe out, they think that bad things go out of the body with the air.
Scientists do not spend much time studying yawning. That is probably because yawning does not hurt. It is just something we do.
1. What does the underlined word “contagious” in Paragraph 2 mean?A.Able to spread quickly. |
B.Able to breathe easily. |
C.Able to change easily. |
D.Able to sleep quickly. |
A.They are too tired or too bored. |
B.A yawn can let good things in. |
C.A yawn can help a warm brain cool down. |
D.A yawn can stretch the muscles in their faces. |
A.Reasons for yawning. |
B.Advantages of yawning. |
C.Disadvantages of yawning. |
D.Different ideas about yawning. |
A.![]() | B.![]() | C.![]() | D.![]() |
相似题推荐
【推荐1】A little knowledge can make a difference at a time of life or death.
What to do when you are inside the building?
Keep calm
What to do after an earthquake?
Do not use your telephone except for a medical or fire emergency (紧急情况). Telephone lines are required for emergency use. Turn off the fridge, TV or computer. Turn off the gas. Wear shoes to protect your feet from debris (碎片).
根据材料内容,从下面五个选项中选出能填入文中空缺处的最佳选项,使短文意思通顺、内容完整。
A.What to do when you are outside the building. |
B.If you are indoors, stay inside. |
C.Check if you are hurt. |
D.If you are in a bus, hold on tight to a strap (带子). |
E.Do you know what to do if you find yourself in an earthquake? |
【推荐2】Is human blood (血液) all the same? Of course not. Blood is made up of different parts, such as red blood cells white blood cells and so on. Two chemical molecules (分子) on the red blood cells make people’s blood different. Scientists mark one molecule “A” and the other molecule “B”.
According to which and how many molecules are on the red blood cell, scientists divide blood into four types: A, B, AB and O. Your blood type will stay the same through the whole life. Scientists have found that people with the same blood type may have things in common.
People with type A: They look peaceful from the outside. But they ask so much of themselves that they may be very nervous inside. They become happy or sad easily. They can easily win people’s trust.
People with type B: They have strong minds. Once they begin a task and make up their minds to do it, they will not give up easily. And they want to do things in their own way.
People with type AB: Maybe they are the strangest among all blood types. They can be both open and shy, noisy and quiet at the same time.
People with type O: They’re open and good at making friends. They always begin tasks but don’t always finish them in the end. They have lots of new ideas and they always strongly believe in themselves.
1. ________ make(s) people’s blood different.A.Two chemical molecules on the red blood cells | B.Two chemical molecules on the white blood cells |
C.Their different kinds of personalities | D.The number of people’s blood cells |
A.can be changed when he grows up | B.decides what his job is |
C.will never change through his life | D.decides what kind of friends he will make |
A.Type A. | B.Type B. | C.Type AB. | D.Type O. |
A.People’s Personalities Depend on Many Things | B.Try to Make Friends with More People |
C.How to Divide people’s blood and Personalities | D.Different blood Types have different Personalities |
【推荐3】When people think of water buffaloes(水牛), they often imagine wild and dangerous animals. But unless they are hurt or angered, water buffaloes are probably the gentlest farm animals in the world. Though they look scary, they are much like household pets. Unlike cattle(黄牛), they are quiet and have a natural fondness for humans.
Water buffaloes are so patient and gentle that there is no need to control them during milking. Because of the animal's calm nature, water buffaloes almost never have their horns(角) taken-off. However, most cattle which are raised for their milk will have their horns taken off, when they are young. It will prevent them from hurting one another when they grow up.
Another common wrong idea is that water buffaloes can be raised only near water. Though they love to roll in muddy water, water buffaloes usually live and have babies in situations where there is not enough water to do this. However, several researchers report that water buffaloes who roll in muddy water do not need to be treated with insecticides(杀虫剂) because the mud(烂泥) coating that forms on their skin protects them from insects and parasites(寄生虫).
Another untrue belief about water buffaloes is that they can live only in tropical areas. Actually, buffaloes are able to live in a wide range of climates. Although they are most common in the tropics, water buffaloes were used to pull snowplows(雪犁) in parts of Europe many years ago.
1. Why are water buffaloes' horns not taken off?A.They don't use their horns to attack. | B.They can't have babies without the horns. |
C.Taking the horns off is dangerous to humans. | D.Taking their horns off can kill the buffaloes. |
A.It protects them from parasites. | B.It washes insecticides off them. |
C.It helps them have more babies. | D.It keeps them cool in hot weather. |
A.People used to keep water buffaloes as household pets. | B.Many people have incorrect ideas about water buffaloes. |
C.Water buffaloes used to be common around the world. | D.Water buffaloes and cattle have many similarities. |
A.Wild animals | B.Fierce cattle | C.Gentle Water buffaloes | D.Water buffaloes' Horn |
【推荐1】People use their mouths for many things. In the English language, there are many expressions using the word “mouth”. But some of them are not so nice.
Sometimes, people say something to a friend or a family member. Later they regret because it hurts that person’s feelings. Or they tell the person something they didn’t mean to tell. The speaker might say: “I really put my foot in my mouth this time.”
Sometimes when one person is speaking, he says the same thing that his friend is going to say. When this happens, the friend might say: “You took the words right out of my mouth!” Sometimes a person has a bad or sad experience with another person. He might say that experience “left a bad taste in my mouth.” Or the person possibly has a very frightening (可怕的) experience, like having an angry dog running after him. He might say: “I had my heart in my mouth.”
Some people have lots of money because they were born into a very rich family. You might say the person “was born with a silver spoon (银勺) in his mouth”. He is the opposite of a person living from “hand to mouth”. This person is very poor and only has enough money for the most important things in life, like food.
1. The underlined word “regret” may mean ________.A.feel sorry | B.feel excited | C.feel proud | D.feel surprised |
A.excited | B.afraid | C.surprised | D.happy |
A.busy | B.hard | C.easy | D.rich |
A.Different Uses of Mouth | B.People and Their Mouths |
C.Expressions about Mouth | D.The Importance of Mouth |
A.In a science fiction. | B.In a travel guide. |
C.In an advertisement. | D.In a culture magazine. |
【推荐2】
I learned to cook at around 12 years old. The first skill I learned was making dough (面团). In my hometown of Ningxia, people make noodles in the evening. Since my parents often came home late, a prepared dough would help my family have supper sooner. I thought it would be easy because I often saw my mom do it—just mix water and flour (面粉), right? Not quite! It turned out to be a mess for a while. First I made the dough too soft. Then I made it too hard. But as I kept trying, I finally made it. I fell in love with cooking. It’s a good way to relax. More importantly, the cooking skill helps me live better when I was alone. I can meal myself instead of waiting for others to feed me.
Besides cooking, I did a lot of farm work in my childhood. I got to know how to plant vegetables. The experience taught me things that many of my peers (同龄人) who grew up in cities still don’t know. For example, I learned that the fruits of peanut plants (花生植株) grow under the soil. I once discussed this with my friends from the city. They thought it was a pity that they didn’t have the chance to learn these things in their lives. The experience of farming brings me a new way to look at the world and teaches me to value everything on my plate.
This may be why I’m so happy to hear that labor education will be required in China. Students in primary and middle schools will have at least one class every week to learn basic household skills like cooking and cleaning. Trust me. These practical skills will help you for the rest of your life.
1. Which cooking skill did the writer master first?A.Cutting vegetables. | B.Making dumplings. |
C.Cracking eggs. | D.Making dough. |
A.By discussing it with her peers. | B.By learning it at school. |
C.By doing it in life. | D.By reading a book about it. |
A.It is necessary and helpful. |
B.It is useless but interesting. |
C.It should be required for adults. |
D.It is mainly about cooking and cleaning. |
A.The writer is an adult with good cooking skill. |
B.The children in the cities are not interested in farm work. |
C.Making dough is not as easy as it looks. |
D.The labor class is valuable for everyone. |
A.What we can learn in villages. |
B.How to plant vegetables. |
C.Life in Chinese villages. |
D.The importance of labor education. |
When you meet English people, they often talk about one thing, the weather. So when you meet someone in England, you say: “Nice weather for the time of year!”
“But it was a little colder yesterday(昨天),” someone may say.
“But it will be a little warmer later!” You can say.
Talk like this and the English people will think, “How friendly you are!” But it’ s not good to ask their age(年龄), or they will not be happy.
1. English people usually _______.
A.talk too much | B.don’t talk too much |
C.go to work by car | D.dance on the train |
A.study | B.sing | C.read | D.dance |
A.the food | B.the age |
C.the weather | D.the clothes |
are _______.
A.cold | B.happy | C.friendly | D.angry |
A.unhappy | B.worried |
C.sad | D.Comfortable |