用來練習英語口語的文章

　　口語交際是人類重要的交際工具。重視口語交際教學是世界各地語文教學的共同趨勢。下面是小編帶來的，歡迎閱讀!

　　篇一

　　Cells and Temperature

　　細胞與溫度

　　Cells cannot remain alive outside certain limits of temperature, and much narrower limits mark the boundaries of effective functioning.

　　細胞只能在一定的溫度範圍記憶體活，而進一步保證它們有效工作的溫度範圍就更小了。

　　Enzyme systems of mammals and birds are most efficient only within a narrow range around 37℃; a departure of a few degrees from this value seriously impairs their functioning. Even though cells can survive wider fluctuations, the integrated actions of bodily systems are impaired. Other animals have a wider tolerance for changes of bodily temperature.

　　哺乳動物和鳥類的酶系統只能在37℃左右的很小範圍內才能有效工作。與此相差僅幾度的溫度都會大大削弱它們的工作效率。儘管溫度變化更大時細胞仍能存活，但機體系統的整體執行能力卻被削弱了。其它動物對體溫的變化有更強的適應性。

　　For centuries it has been recognized that mammals and birds differ from other animals in the way they regulate body temperature. Ways of characterizing the difference have become more accurate and meaningful over time, but popular terminology still reflects the old division into "warm blooded" and "cold blooded" species; warm-blooded included mammals and birds whereas all other creatures were considered cold-blooded. As more species were studied, it became evident that this classification was inadequate. A fence lizard or a desert iguana-- each cold-blooded -- usually has a body temperature only a degree or two below that of humans and so is not cold.

　　幾個世紀以來，人們就認識到哺乳動物和鳥類調節體溫的方式與其它動物不同。隨著時間的推移，人們對這種差異的描述越來越精確和有意義，但是“暖血動物”和“冷血動物”這一古老的分類方式至今仍在大眾詞彙中有所反映。暖血動物包括哺乳動物和鳥類，其它動物統統被視為冷血動物。但是對更多物種進行的研究表明這種分類顯然是不適當的。美洲一種小型蜥蜴和沙漠鬣蜥同屬冷血動物，但實際上它們的體溫通常只比人類的體溫低1-2度，因此並不是真正的冷血。

　　Therefore the next distinction was made between animals that maintain a constant body temperature, calledhomeotherms, and those whose body temperature varies with their environment, called poikilotherms. But this classification also proved inadequate, because among mammals there are many that vary their body temperatures during hibernation. Furthermore, many invertebrates that live in the depths of the ocean never experience changes in the chill of the deep water, and their body temperatures remain constant.

　　因此又出現了恆溫動物***即保持恆定體溫的動物***和變溫動物***即體溫隨外界環境的變化而改變的動物***這一區分方式。但這種分類也不恰當。因為有不少哺乳動物在冬眠期間會改變體溫，而許多生活在深海的無脊椎動物在寒冷的深海水域中體溫並不變化，而是恆定的。

　　篇二

　　Sleep

　　睡眠

　　Sleep is part of a person's daily activity cycle. There are several different stages of sleep, and they too occur in cycles.

　　睡眠是人每天日常活動迴圈的一部分。人的睡眠分幾個階段，而這些階段也是迴圈發生的。

　　If you are an average sleeper, your sleep cycle is as follows. When you first drift off into slumber, your eyes will roll about a bit, your temperature will drop slightly, your muscles will relax, and your breathing well slow and become quite regular. Your brain waves slow down a bit too, with the alpha rhythm of rather fast wavespredominating for the first few minutes. This is called stage 1 sleep. For the next half hour or so, as you relax more and more, you will drift down through stage 2 and stage 3 sleep. The lower your stage of sleep, the slower your brain waves will be. Then about 40 to 60 minutes after you lose consciousness you will have reached the deepest sleep of all. Your brain waves will show the large slow waves that are known as the delta rhythm. This is stage 4 sleep.

　　如果你是一個正常的睡眠者，你的睡眠迴圈會這樣進行。在你開始昏昏入睡時，你的眼睛會滾動幾下，體溫略有下降，肌肉放鬆，呼吸變得緩慢而有節奏。除了開始幾分鐘比較快的α節奏外，腦電波也稍有減緩。這被稱為第一階段睡眠。在隨後約半小時內，你進一步放鬆，進入第二和第三階段睡眠。睡眠越深入，腦電波就越緩慢。大約在開始睡眠後的40到60分鐘，你將進入沉睡狀態。這時的腦電波表現為巨大的緩波，被稱為δ節奏。這就是第四階段睡眠。

　　You do not remain at this deep fourth stage all night long, but instead about 80 minutes after you fall into slumber, your brain activity level will increase again slightly. The delta rhythm will disappear, to be replaced by the activity pattern of brain waves. Your eyes will begin to dart around under your closed eyelids as if you were looking at something occurring in front of you. This period of rapid eye movement lasts for some 8 to 15 minutes and is called REM sleep. It is during REM sleep period, your body will soon relax again, your breathing will grow slow and regular once more, and you will slip gently back from stage 1 to stage 4 sleep - only to rise once again to the surface of near consciousness some 80 minutes later.

　　但你並不是整夜都保持這種沉睡狀態。入睡後約80分鐘左右，你的大腦運動水平會再度略有提高。δ節奏消失，並被腦電波的運動圖形取代。你的眼睛會在閉著的眼瞼下迅速轉動，就好象你在看著眼前發生的什麼事情。這種迅速的眼球運動持續約8-15分鐘，這一階段睡眠被稱之為快速眼動***REM***睡眠。在REM睡眠階段，你的肢體會很快再度放鬆，呼吸也再次放慢並變得有節奏，你會輕鬆地從第一階段滑入第四階段睡眠——直到大約80分鐘後重新接近清醒狀態。

　　篇三

　　Bacteria

　　細菌

　　Bacteria are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousandth of a millimeter: a pinhead is about a millimeter across. Rod-shaped bacteria are usually from two to four microns long, while rounded ones are generally one micron in diameter. Thus if you enlarged a rounded bacterium a thousand times, it would be just about the size of a pinhead. An adult human magnified by the same amount would be over a mile tall.

　　細菌是極其微小的生物體。我們用英寸或釐米來測量自己的大小，而測量細菌卻要用微米。一微米等於千分之一毫米。針頭直徑大約一毫米。棒狀細菌通常有2-4微米長，而圓形細菌的直徑一般只有1微米。因此，即使你把一個圓形細菌放大1000倍，它也不過一個針頭那麼大。可是如果把一個成年人放大1000倍，就會變成1英里***或1.6公里***多高。

　　Even with an ordinary microscope, you must look closely to see bacteria. Using a magnification of 100 times, one finds that bacteria are barely visible as tiny rods or dots. One cannot make out anything of their structure. Using special stains, one can see that some bacteria have attached to them wavy-looking "hairs" called flagella. Others have only one flagellum. The flagella rotate, pushing the bacteria through the water. Many bacteria lack flagella and cannot move about by their own power, while others can glide along over surfaces by some little-understoodmechanism.

　　用一般的顯微鏡觀察細菌時，你必須仔細觀察才能看見它們。使用100倍的顯微鏡時，你會發現細菌不過是隱約可見的小細棒或小點點，而它們的結構你卻根本看不出來。使用特殊的著色劑後，你會發現有的細菌上長著不少波狀的"毛髮"即鞭毛，而有的細菌只有一根鞭毛。鞭毛的旋轉可以推動細菌在水中行進。不少細菌沒有鞭毛，因而不能自己行進。還有些細菌卻能通過某些鮮為人知的機制沿物體表面滑動。

　　From the bacteria point of view, the world is a very different place from what it is to humans. To a bacterium water is as thick as molasses is to us. Bacteria are so small that they are influenced by the movements of the chemical molecules around them. Bacteria under the microscope, even those with no flagella, often bounce about in the water. This is because they collide with the watery molecules and are pushed this way and that. Molecules move so rapidly that within a tenth of a second the molecules around a bacteria have all been replaced by new ones; even bacteria without flagella are thus constantly exposed to a changing environment.

　　我們所熟知的世界在細菌眼中完全是另一個樣子。對於細菌來說，水就同糖漿之於人類一樣稠密。細菌是如此的微小，周圍化學分子的一舉一動都會對它們產生影響。在顯微鏡下，細菌，甚至包括那些沒有鞭毛的細菌，經常在水中跳來跳去。這是因為它們與水分子相撞後，被彈向各個方向。分子移動很迅速，僅0.1秒之隔，一個細菌周圍的分子就會完全更新。因此，即使是沒有鞭毛的細菌也暴露在一個不斷變化的環境中。