2016年12月大學(xué)英語四級閱讀模擬練習(xí)(23)

　　Sleep 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 first drift off into slumber (安睡), your eyes will roll about a bit, your temperature will drop slightly, your muscles will relax, and your breathing were 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.

　　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 (眼皮) 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.

　　1.The stages of sleep take on ____.

　　A) an irregular aspect. B) a regular aspect C) a punctual aspect D) a similar aspect

　　2.Stage 4 sleep lasts ____.

　　A) about 80 minutes

　　B) about 40 60 minutes

　　C) about 30 munutes

　　D) about 20 40 minutes

　　3.The brain waves are the slowest during ____.

　　A) stage 1 C) stage 4 B) stage 2 and stage 3 D) REM sleep

　　4.In the second paragraph the word “dart” means ____.

　　A) glare B) move rapidly or suddenly C) stop moving D) gaze

　　5.One of the features of REM sleep is that ____.

　　A) there are large slow waves, though rapid for the first few minutes

　　B) you have the deepest sleep

　　C) there are no brain waves

　　D) the brain waves are a little fast and the brain becomes a little active

　　參考答案：

　　1.答案B。文章的第二句告訴我們睡眠的不同階段是周期性發(fā)生的，故睡眠的各階段呈現(xiàn)規(guī)則的一面。

　　2.答案D。根據(jù)文章可知一個睡眠周期大約是 80分鐘，而stage 4 sleep是睡眠的最后階段，它發(fā)生在入睡后大約40至60分鐘時，據(jù)此可推出stage 4 sleep持續(xù)20至40分鐘。

　　3.答案C。文章第一段倒數(shù)第四句說“睡得越深，腦電波就越慢”，而 stage 4 sleep 是睡得最深的，故腦電波也是最慢的。

　　4.答案B。dart的后文說“眼睛好像看著發(fā)生在眼前的事”，又說“這種快速移動眼睛的階段叫 REM sleep”，據(jù)此可知dart意為move quickly or suddenly(飛快地移動)。glare怒目而視;gaze凝視。

　　5.答案D。從第二段第一、二句可知大腦運(yùn)動水平會再度略有提高，而 delta波消失， 取代的是腦電波運(yùn)動圖形。據(jù)此可知腦電波變得快了一點(diǎn)，大腦活躍些。而大的緩波和睡得 最深是 stage 4 sleep的特征，rapid for the first few minutes是stage 1 sleep的特征，整個睡眠階段都是有腦電波的，故A，B和C皆錯。