備考雅思英語閱讀材料

　　雅思考試(IELTS)，全稱國際英語語言測試系統(tǒng)，是一種針英語能力，為打算到使用英語的國家學(xué)習(xí)、工作或定居的人們設(shè)置的英語水平考試。為了幫助大家備考雅思，小編分享了一些英語閱讀材料，歡迎閱讀!

　　克隆

　　Nearly all living organisms have parents in which they were reproduced and born through various stages of the life cycle. Whether it is a human being with a mother and a father or a chicken hatching from an egg, most living organisms have male and female parents. Some living organisms also form from one parent such as when a single-celled amoeba splits into two to reproduce offspring.

　　幾乎所有的生命體在生命周期的不同階段都有雙親孕育和培養(yǎng)。無論是有父母雙親的人類還是從一只從雞蛋孵化而成的雞，大部分生命體有兩性親代。也有一些生物體形成于單一親代，例如單細(xì)胞變形蟲分裂成兩個(gè)從而繁衍后代。

　　However, there is a process which is much different in producing offspring called cloning. Cloning is the process when scientists take DNA from an animal cell and then place it or implant it into an egg cell taken from another animal. Before placing though, the DNA from the cell receiving it is removed.

　　然而，克隆這種繁殖后代的方法大相徑庭�？寺∈强茖W(xué)家在動(dòng)物細(xì)胞提取DNA然后將其放入或植入其他動(dòng)物卵細(xì)胞的過程。在植入之前，受體細(xì)胞內(nèi)的DNA被移除。

　　An example of cloning, which made history in 1997, was when scientists successfully cloned a sheep. The new sheep's name was Dolly, and she was not born in the usual manner. Instead, she became an exact copy of her mother, similar to an identical twin. It would be nearly the same as taking the DNA from the son of a mother, placing the DNA in the egg cell of another woman, but first removing the woman's own DNA, and then allow the growth of the new cell in the woman. Nine months later there would be an exact copy of the mother's son born to the woman.

　　克隆史上的首例是科學(xué)家在1997年成功克隆羊。取名為多莉的克隆羊以非常規(guī)方式孕育而成。然而，她與其母本完全一致，類似于同卵雙生。這與采集兒子母親的DNA后放入另一個(gè)女人的已除去其本身DNA的卵細(xì)胞中，然后新細(xì)胞的在女人體內(nèi)生長。九個(gè)月后女人便產(chǎn)下與其兒子母親完全一致的男嬰。

　　In the case of cloning, a father is not needed. In the first successful cloning of an animal the DNA molecule had all of the information needed to create a clone, Dolly. The DNA molecules contains the genetic code, which is basically directions for the new offspring. Normally, a new organism gets half of this code from the father and the other half from the mother. When these two cells are joined together they divide millions of times and then grow into the millions of cells which form the body of the animal. Each cell of the body has a copy of the genetic code and all it would need is an egg cell to grow.

　　克隆不需要父本。第一個(gè)成功的動(dòng)物克隆中，DNA分子攜帶了克隆羊多莉所需的所有信息。 DNA分子中包含的遺傳密碼基本就是新生子代的方向。通常一個(gè)新的有機(jī)體得到父母親雙方各一半的遺傳密碼。兩個(gè)生殖細(xì)胞結(jié)合后經(jīng)過上百萬次分裂生成數(shù)百萬個(gè)細(xì)胞，構(gòu)成了動(dòng)物體。體內(nèi)每一個(gè)細(xì)胞都復(fù)制了遺傳密碼，而它所需要的不過是孕育其生長的卵細(xì)胞。

　　So with cloning one of those cells is used and then the cell is simply placed in to the egg cell of the carrier. In the sheep example, the carrier was a female sheep. For Dolly, a single cell was used from the udder of her mother. The DNA in her mother's cell was removed and then transferred to an egg cell of another sheep. About five months later Dolly was born without a father and a copy or clone of her mother.

　　因此克隆就是將親本的體細(xì)胞中的一個(gè)植入載體的卵細(xì)胞中。利用多莉母親的乳房的一個(gè)細(xì)胞，將該細(xì)胞的DNA移植到另一只羊的卵細(xì)胞。大約五個(gè)月后，沒有父親的多莉出生，與其母親完全一致，是其母的克隆。

　　Though no humans have ever been fully cloned, human embryos have been cloned. Currently it may not be taking place, but in the future it may happen, but today it is rare. In the movies about Jurassic Park, cloning took place to create the dinosaurs, though it was a fictional movie, much of the science behind the process can be real.

　　雖然沒有完全的克隆人，但曾有克隆的人類胚胎�？寺∪四壳半y以實(shí)現(xiàn)，但將來卻可能成真，但至今仍然罕見。侏羅紀(jì)公園的電影中，克隆用于創(chuàng)造恐龍，雖然這是一個(gè)虛構(gòu)的電影，該過程后的科學(xué)大多是真實(shí)的。

　　Though there are fully developed human clones, other fully developed animals have been cloned besides sheep. They include the rhesus monkey, pig, cattle, cat, rabbit, deer, horse, a few others, and of course mice. Cloning also involves many, many failed attempts before it becomes successful. For instance, Dolly the sheep was not born until after 276 failed attempts. The only true successful cloning takes place when identical twins are born, but they came from a father and a mother. The cloned animals may also experience health problems.

　　盡管有發(fā)育完全的人類克隆，除了多莉羊外其他發(fā)育完全的動(dòng)物克隆，如獼猴，豬，牛，貓，兔，鹿，馬等等，當(dāng)然也有老鼠。克隆成功前還有很多失敗的嘗試。例如，多莉是276失敗的嘗試后才出生的。唯一真正成功的克隆是同卵雙胞胎，但他們是源于同父同母。克隆動(dòng)物也可能會(huì)遭受健康問題。

　　In summary, cloning is basically creating another organism without the father involved, and the clone is an exact copy of the mother with the same genetic code. However, if cloning ever became 100% successful, the clones may look alike, but it would not mean they would behave in the same way.

　　總之，克隆基本上就是不需要父方生育后代且后代完全復(fù)制起母親。但是，100%成功的克隆，即使外表相似，但并不意味著它們的行為會(huì)一致。

　　The respiratory system of the human body is responsible for the distribution of the air inhaled and exhaled throughout a person's life. The respiratory system includes the nose, throat, voice box, wind pipe, and lungs.

　　呼吸系統(tǒng)

　　人體的呼吸系統(tǒng)負(fù)責(zé)人一生吸入和呼出空氣的氣體交換。呼吸系統(tǒng)包括鼻、喉嚨、喉頭、氣管和肺。

　　Each time a person inhales, or breathes in air, several kinds of gases enter the body. The most important is oxygen because it keeps a person alive, and the cells of the body need it for energy and growth. The air enters through the nose and mouth and the lungs fill up and then empty out. When the air is inhaled there are tiny hairs in the nose called cilia that filter the air. The air is also warmed and moistened as it travels through the nose. Cilia also protects other parts of the respiratory passages, filtering out dust and other particles.

　　每次人體吸入空氣，會(huì)有幾種氣體的進(jìn)入人體。最重要的是氧氣，因?yàn)樗�是人的生存需要氧氣，并且人體細(xì)胞需要氧氣用于制造能量和生長�？諝馔ㄟ^鼻子和嘴進(jìn)入，填滿肺部，然后排空。當(dāng)空氣被吸入時(shí)，鼻子內(nèi)的纖毛過濾空氣。鼻腔同樣也溫潤了吸入的空氣。而且鼻毛還過濾掉了吸入的灰塵和其他顆粒。

　　The inhaled air travels through the windpipe, which is called the trachea. The human body contains two lungs. The lungs are pink, mushy, and like a sponge. The lungs are protected by the rib cage and keeps them protected and safe. The lung on the left side of the body is smaller than the right lung, which allows room for a person's heart. Beneath the lungs is a muscle called the diaphragm. It works with the lungs to allow a person to inhale and exhale. When a person breathes in the diaphragm shrinks and levels out as the lungs fill up with air.

　　吸入的空氣穿過氣管。人體有兩葉肺。肺是粉紅色的糊狀體，像海綿一樣。肺部由肋籠保護(hù)。人體左側(cè)的肺比右肺更小，因?yàn)樽髠?cè)的心臟同樣需要空間。肺的下部是膈肌。它與肺部協(xié)同工作使人體進(jìn)行吸氣和呼氣。當(dāng)一個(gè)人的吸氣，膈肌收縮，肺部充滿空氣。

　　The end of the trachea is located between the two lungs. At the bottom of the trachea are a couple of large tubes called bronchi. The bronchi lead into the lungs. One tube sends air into the left lung, and the other tube sends air into the right lung.

　　氣管的尾部在兩肺之間。在氣管的底部有幾個(gè)大的管道成為支氣管。支氣管與肺部直接相連。一個(gè)支氣管使空氣進(jìn)入左肺和另一支氣管使空氣進(jìn)入右肺。

　　Once the air travels through the bronchi, it will branch off into smaller tubes called bronchioles. The bronchioles are about the thickness of a hair, and there are about 30,000 in each lung. From the bronchioles the air then continues its journey to tiny air sacs located throughout the lungs. The tiny air sacs are called alveoli.

　　空氣進(jìn)入支氣管后，它將岔開成更小的細(xì)支氣管。細(xì)支氣管約為與頭發(fā)粗細(xì)相當(dāng)，每個(gè)肺約有30,000個(gè)細(xì)支氣管。進(jìn)入細(xì)支氣管空氣再繼續(xù)穿過遍布肺部的微小氣囊。而微小氣囊被稱為肺泡。

　　The 600 million alveoli are covered with very tiny blood vessels called capillaries. It is in this area of the lungs between the alveoli and capillaries the exchange of air takes place. Alveoli allow the air to pass into the blood cells of the body, first traveling through the heart carried by red blood cells. The oxygen enters the blood through the tiny capillaries. The heart then takes the blood filled with oxygen and sends it out to all the cells of the body.

　　6億個(gè)肺泡上都覆蓋著非常微小的血管稱為毛細(xì)血管。肺泡與肺泡之間以及毛細(xì)血管之間發(fā)生的便是肺部的空氣交換。肺泡讓空氣進(jìn)入人體血細(xì)胞，首先就是通過紅血細(xì)胞將空氣運(yùn)送到心臟。氧氣通過毛細(xì)血管進(jìn)入血液。然后心臟吸收充滿氧氣的血液并將其運(yùn)輸?shù)降缴眢w的所有細(xì)胞中。

　　When a person exhales or breathes out everything will happen in reverse. The diaphragm relaxes and the lungs become smaller. The cells in the body have received the oxygen it needs, but carbon dioxide must leave the body. This time, wastes enter the alveoli through the capillaries, back through the bronchioles and bronchi, and then the trachea and out through the nose and mouth. The air is warm because it heats up as it travels through the body.

　　當(dāng)一個(gè)人呼氣或吐氣則一切相反。隔膜松弛，肺部變小。體內(nèi)的細(xì)胞已接收其所需的氧氣，但二氧化碳必須排出身體。此時(shí)，廢物通過毛細(xì)血管進(jìn)入肺泡，并回到細(xì)支氣管和支氣管，然后通過氣管、鼻子和嘴排除。呼出的空氣因?yàn)榇┻^體內(nèi)而變得溫暖。

　　Finally, the lungs are also important for talking. The larynx is located above the trachea, which is often called the voice box. Vocal cords across the larynx open and close, and then vibrate, to create the sounds as air flows between them. The amount of air exhaled determines the loudness of a sound.

　　最后，肺部對于發(fā)聲也很重要。喉位于氣管，這一部分也被稱為喉頭。喉頭的開合以及聲帶的振動(dòng)使得其間的空氣以及人體發(fā)聲。呼出的空氣的量決定了聲音的響度。

　　In summary, there are many parts of the respiratory system working together to distribute oxygen throughout the body, as well as the lungs being necessary for a person's ability to talk. It is important to keep the lungs healthy and strong.

　　呼吸系統(tǒng)是許多器官協(xié)同作用將氧氣分散到身體的各個(gè)部分，而肺也是一個(gè)人發(fā)聲的重要器官。保證肺部的健康和強(qiáng)大是非常重要的。