新东方优美短文背诵 Unit49:Sleep
新东方优美背诵短文50篇 Unit49:Sleep
49 Sleep
Sleet is part of a person’s daily activity cycle. There are several different stages of sleep, and they too occur in cycles. If you are an average sleeper, your sleep cycle is as follows. When you fist drift off into slumber, your eyes will roll about a bit, you temperature will drop slightly, your muscles will relax, and your breathing well slow and become quite regular. Your brain waves slow and become quite regular. Your brain waves slow down a bit too, with the alpha rhythm of rather fast waves 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. slower your brain waves will be. Then about 40to 69 minutes after you lose consciousness you will have reached the deepest sleep of all. Your brain will show the large slow waves that are known as the delta rhythm. This is stage 4 sleep.
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 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.
睡眠
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。如果你是一个正常的睡眠者，你的睡眠循环会这样进行。
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。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高。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，这一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。
NSDA“SDcamps”全国英语演讲与辩论大赛（大学组）/SDcamps全国中小学生英语演讲与辩论大会（中小学及幼儿组）/美式辩论赛（以下简称大赛/大会）现诚招全国省市合作伙伴或城市合伙人，共同进行推广NSDA赛事品牌、举办赛事及培训活动、开展素质教育、美式营地项目等多方面合作。
我们希望认同NSDA理念，有赛事组织经验，或有教育资源，特别是有理想有热情的机构或个人一起携手，共同推广NSDA品牌、赛事及素质教育。以机构的形式，或以城市合伙人的方式均可。具体的赛事组织、盈利模式，欢迎电话或微信咨询。
微信：0012133598196
