雅思考試(IELTS)，全稱國際英語語言測試系統，是一種針英語能力，為打算到使用英語的國家學習、工作或定居的人們設定的英語水平考試。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週期的不同階段都有雙親孕育和培養。無論是有父母雙親的人類還是從一隻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於單一親代，例如單細胞變形蟲分裂成兩個從而繁衍後代。
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，克隆這種繁殖後代的方法大相徑庭。克隆是科學家在動物細胞提取DNA然後將其放入或植入其他動物卵細胞的過程。在植入之前，受體細胞內的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家在1997年成功克隆羊。取名為多莉的克隆羊以非常規方式孕育而成。然而，她與其母本完全一致，類似於同卵雙生。這與採集兒子母親的DNA後放入另一個女人的已除去其本身DNA的卵細胞中，然後新細胞的在女人體內生長。九個月後女人便產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。第一個成功的動物克隆中，DNA分子攜帶了克隆羊多莉所需的所有資訊。 DNA分子中包含的遺傳密碼基本就是新生子代的方向。通常一個新的有機體得到父母親雙方各一半的遺傳密碼。兩個生殖細胞結合後經過上百萬次分裂生成數百萬個細胞，構成了動物體。體內每一個細胞都複製了遺傳密碼，而它所需要的不過是孕育其生長的卵細胞。
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胞中的'一個植入載體的卵細胞中。利用多莉母親的乳房的一個細胞，將該細胞的DNA移植到另一隻羊的卵細胞。大約五個月後，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。克隆人目前難以實現，但將來卻可能成真，但至今仍然罕見。侏羅紀公園的電影中，克隆用於創造恐龍，雖然這是一個虛構的電影，該過程後的科學大多是真實的。
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.
儘管有發育完全的人類克隆，除了多莉羊外其他發育完全的動物克隆，如獼猴，豬，牛，貓，兔，鹿，馬等等，當然也有老鼠。克隆成功前還有很多失敗的嘗試。例如，多莉是276失敗的嘗試後才出生的。唯一真正成功的克隆是同卵雙胞胎，但他們是源於同父同母。克隆動物也可能會遭受健康問題。
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後代且後代完全複製起母親。但是，100%成功的克隆，即使外表相似，但並不意味著它們的行為會一致。
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
人體的呼吸系統負責人一生吸入和撥出空氣的氣體交換。呼吸系統包括鼻、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，會有幾種氣體的進入人體。最重要的是氧氣，因為它是人的生存需要氧氣，並且人體細胞需要氧氣用於製造能量和生長。空氣通過鼻子和嘴進入，填滿肺部，然後排空。當空氣被吸入時，鼻子內的纖毛過濾空氣。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。人體左側的肺比右肺更小，因為左側的心臟同樣需要空間。肺的下部是膈肌。它與肺部協同工作使人體進行吸氣和呼氣。當一個人的吸氣，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大的管道成為支氣管。支氣管與肺部直接相連。一個支氣管使空氣進入左肺和另一支氣管使空氣進入右肺。
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.
空氣進入支氣管後，它將岔開成更小的細支氣管。細支氣管約為與頭髮粗細相當，每個肺約有30,000個細支氣管。進入細支氣管空氣再繼續穿過遍佈肺部的微小氣囊。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.
6億個肺泡上都覆蓋著非常微小的血管稱為毛細血管。肺泡與肺泡之間以及毛細血管之間發生的便是肺部的空氣交換。肺泡讓空氣進入人體血細胞，首先就是通過紅血細胞將空氣運送到心臟。氧氣通過毛細血管進入血液。然後心臟吸收充滿氧氣的血液並將其運輸到到身體的所有細胞中。
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.
當一個人呼氣或吐氣則一切相反。隔膜鬆弛，肺部變小。體內的細胞已接收其所需的氧氣，但二氧化碳必須排出身體。此時，廢物通過毛細血管進入肺泡，並回到細支氣管和支氣管，然後通過氣管、鼻子和嘴排除。撥出的空氣因為穿過體內而變得溫暖。
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.
最後，肺部對於發聲也很重要。喉位於氣管，這一部分也被稱為喉頭。喉頭的開合以及聲帶的振動使得其間的空氣以及人體發聲。撥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.
呼吸系統是許多器官協同作用將氧氣分散到身體的各個部分，而肺也是一個人發聲的重要器官。保證肺部的健康和強大是非常重要的。
