根据材料请回答 36～40 题 SleepSleep is part of your daily activity cycle, but there are

根据材料请回答 36～40 题

Sleep

Sleep is part of your daily activity cycle, but there are several differenttypes or stages of sleep and they too occur in cycles.If you are an average sleeper, your sleep cycle will go something like this： When you first drift off into sleep your eyes will roll about a bit, your temperature will drop slightly, your muscles will relax, and your breathing will slow and become quite regular.Your brain waves slow down a bit too.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 40-60 minutes after you lose consciousness, you will have reached the deepest sleep of all.Your brain waves will show the delta rhythm.This is Stage 4 sleep.

You may think that you stay at this deep fourth stage all the rest of the night, but that turns out not to be the case.Instead, about 80 minutes after you fall into sleep your activity cycle wilt increase slightly.The delta rhythm will disappear, to be replaced by the activity pattern of brain waves.Your eyes will begin to move around under your closed eyelids as if you were looking at something occurring in front of you.This period of Rapid Eye Movements lasts for some 8-15 minutes and is called REM sleep.During both light and deep sleep, the muscles in your body are relaxed but capable of movement.However, as you slip into REM sleep, a very odd thing occurs.Most of the voluntary muscles(随意肌)in your body become paralyzed(麻痹).Although your brain shows very rapid bursts of neural activity during REM sleep, your body is incapable of moving.

第 36 题 The lower the stage of sleep

A．the greater the alpha waves will be

B．the slower the brain waves will appear

C．the slower the activity pattern of the brain

D．the deeper the sleeper gets to unconsciousness