新概念优美背诵短文【三篇】

新概念优美背诵短文【三篇】

【睡眠】

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动循环的一部分。人的睡眠分几个阶段，而这些

阶段也是循环发生的。

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 waves predominating 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.

如果你是一个正常的睡眠者，你的睡眠循环会这样实行。在你开始昏

昏入睡时，你的眼睛会滚动几下，体温略有下降，肌肉放松，呼吸变

得缓慢而有节奏。除了开始几分钟比较快的α节奏外，脑电波也稍有减缓。这被称为第一阶段睡眠。在随后约半小时内，你进一步放松，进入第二和第三阶段睡眠。睡眠越深入，脑电波就越缓慢。大约在开始睡眠后的40到60分钟，你将进入沉睡状态。这时的脑电波表现为巨大的缓波，被称为δ节奏。这就是第四阶段睡眠。

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.

但你并不是整夜都保持这种沉睡状态。入睡后约80分钟左右，你的大脑运动水平会再度略有提升。δ节奏消失，并被脑电波的运动图形取代。你的眼睛会在闭着的眼睑下迅速转动，就好象你在看着眼前发生的什么事情。这种迅速的眼球运动持续约8-15分钟，这个阶段睡眠被称之为快速眼动(REM)睡眠。在REM睡眠阶段，你的肢体会很快再度放松，呼吸也再次放慢并变得有节奏，你会轻松地从第一阶段滑入第四阶段睡眠——直到大约80分钟后重新接近清醒状态。

【细胞与温度】

Cells and Temperature

细胞与温度

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

细胞只能在一定的温度范围内存活，而进一步保证它们有效工作的温

度范围就更小了。

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.

哺乳动物和鸟类的酶系统只能在37℃左右的很小范围内才能有效工作。与此相差仅几度的温度都会大大削弱它们的工作效率。即使温度变化

更大时细胞仍能存活，但机体系统的整体运行水平却被削弱了。其它

动物对体温的变化有更强的适合性。

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.

几个世纪以来，人们就理解到哺乳动物和鸟类调节体温的方式与其它动物不同。随着时间的推移，人们对这种差异的描述越来越精确和有意义，但是“暖血动物”和“冷血动物”这个古老的分类方式至今仍在大众词汇中有所反映。暖血动物包括哺乳动物和鸟类，其它动物统统被视为冷血动物。但是对更多物种实行的研究表明这种分类显然是不适当的。美洲一种小型蜥蜴和沙漠鬣蜥同属冷血动物，但实际上它们的体温通常只比人类的体温低1-2度，所以并不是真正的冷血。

Therefore the next distinction was made between animals that maintain a constant body temperature, called homeotherms, 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.

所以又出现了恒温动物（即保持恒定体温的动物）和变温动物（即体温随外界环境的变化而改变的动物）这个区分方式。但这种分类也不恰当。因为有很多哺乳动物在冬眠期间会改变体温，而很多生活在深海的无脊椎动物在寒冷的深海水域中体温并不变化，而是恒定的。

【钢琴】

Piano

钢琴

The ancestry of the piano can be traced to the early keyboard instruments of the fifteenth and sixteenth centuries -- the spinet, the dulcimer, and the virginal. In the seventeenth century the organ, the clavichord, and the harpsichord became the chief instruments of the keyboard group, a supremacy they

maintained until the piano supplanted them at the end of the eighteenth century.

钢琴的家系能够追溯至15至16世纪早期的键盘乐器，包括小型拨弦琴、洋琴和维金娜琴。17世纪时风琴、敲弦琴和拨弦琴成为键盘乐器类的主要成员。这种至高无上的地位一直为它们所保持，直到18世纪末期钢琴将它们取代。

The clavichord's tone was metallic and never powerful; nevertheless, because of the variety of tone possible to it, many composers found the clavichord a sympathetic instrument for intimate chamber music.

敲弦古钢琴的音调有金属的音质，缺乏雄劲。不过因为它的音调变化多，很多作曲家发现对于亲切的室内乐是一种得体的乐器。

The harpsichord with its bright, vigorous tone was the favorite instrument for supporting the bass of the small orchestra of the period and for concert use, but the character of the tone could not be varied save by mechanical or structural devices.

人们最喜欢用具备明快有力音调的拨弦古钢琴来配合当时小型管弦乐团的低音乐器以及在演奏会上演奏。但它的音调难以变化，除非使用机械或构件装置。

The piano was perfected in the early eighteenth century by a harpsichord maker in Italy(though musicologists point out several previous instances of the instrument).This instrument was called a piano e forte (soft and loud), to indicate its dynamic versatility; its strings were struck by a recoiling hammer with a felt-padded head.

18世纪早期的意大利，钢琴在一位拨琴钢琴制造者手中得到完善（即

使音乐理论家们指出有更早的例子）。这种乐器被称为piano e

forte（意大利语，柔和而响亮的），以显示它有力的多样性。演奏

者用一个头部带皮毡的弹击乐锤敲击琴弦。

The wires were much heavier in the earlier instruments. A series of mechanical improvements continuing well into the nineteenth century, including the introduction of pedals to sustain tone or to soften it, the perfection of a metal frame, and steel wire of the finest quality, finally produced an instrument capable of myriad tonal effects from the most delicate harmonies to an almost orchestral fullness of sound, from a liquid, singing tone to a sharp, percussive brilliance.

更早的这种乐器之上的金属丝要重得多。从此，持续到19世纪的一系

列机械上的改进，包括引入踏板以维持音调或使其柔和，改善金属框架，以及使用性能的钢丝，最终产生了一种具备无数音调效果的乐器。这些效果涵盖了从最精致的和声到几乎全部的管弦乐音响，从明快流

畅的吟唱的音调到尖锐的打击乐器的清晰动人的恢宏气势。