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What does fizz (气泡) taste like? In Bubbly (多泡的)drinks such as sodas, tiny bubbles give the drink a lift--- and have a distinct taste, In a new study on mice, scientists have connected that fizzy-taste feeling to the ability to taste sourness, such as that of oranges or vinegar. Scientists first thought the taste of bubbles came from the bubbles bursting on the tongue, but now ate starting to think differently. Charles Zuker, of Columbia University, and his team studied the nervous system of mice to understand how the tongue tastes carbon dioxide, which is the gas that makes up the bubbles. Animals, including human beings, are able to detect different tastes by using taste buds(味蕾) which pick up tastes in the mouth, and then send them to the brain. In the experiment, different groups of mice were genetically engineered to be missing one of the senses involved in taste. “Genetically engineered” means the researchers were able to turn off the switches for certain senses by changing the genes responsible for taste. The mice in one group could not taste sweet; another, sour; the third, bitter, and the fourth, salt. When the scientists gave carbon dioxide to the mice, the nervous systems of all the mice responded to the gas, except those of the mice that could not taste sour. This shows that the taste of the bubbles must be sour, and that by turning off the ability of the mice to taste sour, the scientists also turned off their ability to taste carbon dioxide. When they studied the cells that detect sourness, the researchers found a protein attached to the cells that is important to the process of tasting carbon dioxide. When carbon dioxide comes into contact with this protein, the protein knocks off particles called protons. These protons(质子), in turn, travel to the brain, which says ,” Hey! That’s a taste!” It may seem like a lot of work to get from a can of soda to a taste, but the science of the senses is anything but simple, “ Taste is a challenging system to study,” one researcher says. 72. What is the most important function of the bubbles? A. To look interesting . B. To make drinks taste good. C. To make drinks funny. D. To produce a lot of fizz. 73. From the experiment the researchers learned that______. A. sourness has nothing to do with the taste of bubbles. B. there is a connection between sourness and bubbles. C. the taste of bubbles is better if it’s less sour. D. most mice cannot taste carbon dioxide. 74. It can be inferred from the passage that ________. A. the taste of bubbles is produced by the bubbles bursting on the tongue. B. the nervous systems of mice show how the tongue tastes carbon dioxide. C. taste seems simple but is very complex to research. D. nerve cells sending signals to the brain is the first step in tasting something. 75. Which of the following would be the best title for the passage? A. Nervous Systems Understand How the Tongue Tastes. B. The Process of Taste C. The taste of Bubbles. D. Different Animals Detect Different Tastes. 第四部分：写作(共两节，满分35分) 第一节：对话填空(共10小题，每小题1分，满分10分) T=Todd A=Adrienne T: I was looking at your photos, and I found you can play the violin. Tell me about it. A: I really (76) e______ playing the violin. I’ve been playing for many years 76________ since I was a five-year-old girl. Everyone in my family plays an (77) i_________, 77_________ so it’s part of what we do together as a family. T: So when you were (78) l _________ you practiced every day , didn’t you?78_________ A: Yes, I did, my mom made me. I didn’t have a (79) c__________. 79_________ T: Did you have a (80) t________ come over to your house?80_________ A: No, I had a lesson at the violin school once a week and I (81)a__________ group lessons too, so it was once a week with a private81________ and once a week with a group. T: When did you stop playing? A: I haven’t stopped. T: Oh, you (82)s_______ practice.82________ A: Yeah, although I don’t have my violin here in Japan right now. T: Is it (83) h_______ to be away from your violin?83_________ A: It’s sometimes, I (84) m________ the time when I played with my family.84_________ T: So are you going to play the violin for me sometime? A: Sure! If you can (85) f________ a violin, I will. 85________ 第二节：书面表达(满分25分) 假设你是某中学老师李红, 请给你的朋友张华写一封信,告诉他你第一天上课的情况, 主要内容如下: 1.描述一件课堂上令你印象深刻的事情; 2.介绍你处理该事的方法; 3.谈谈你的感想. 注意：1. 可以适当增添细节 2. 词数不少于120个; 3. 文章不得出现与本人及学校相关的任何真实信息 高一年级英语期末考试答案 I.听力 ABACB BCBCC AAABC ABABC II.单选BACAD BBBCC AACDB III.完形BDCAB DCBAC BDCAB ABDAB IV.阅读 CDAD BCA CDDAB CCAD BBCC V.对话填空 1. enjoy2. instrument3. little 4. choice 5. teacher 6. attended 7.still8. hard 9.miss 10. find VI.书面表达 Dear zhanghua, Long time no see! I miss you very much. Now I am so excited that I can’t wait to share with you an unforgettable experience. I gave my first lesson today, which left me a deep impression. Seeing a young teacher enter the classroom, my students began to make noise. I stood on the platform, feeling embarrassed and not knowing what to do .Then I realized something must be done. I asked the kids whether they liked English songs. After taking a deep breath, I sang a song I had practiced many times. To my surprise, all the kids were concentrating on my class later on. How delighted I am now! Actually, whatever happens , we must stay calm first and then find a wise solution. Looking forward to your reply. Yours Li Hong (责任编辑：admin) |