2. 职称英语
  3. When you first drift off into slumber, your eyes will roll about a bit, your

When you first drift off into slumber, your eyes will roll about a bit, your

游客2025-01-18  16
问题     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 will become quite regular. Your brain waves slow down a bit, with the alpha rhythm predominating for the first few minutes. This is the first stage of sleep. For the next 30 minutes or so, you will drift down through Stage 2 and Stage 3. The lower your stage of sleep, the slower your brain waves will be. About 40—60 minutes after you lose consciousness, you will reach the last stage. Your brain waves will show the delta rhythm.
    You may think that you stay at this deep stage all the rest of the night, but that turns out not to be the case. About 80 minutes after you fall into slumber, your activity cycle will increase 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. This period of Rapid Eye Movements lasts for 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. As you slip into REM sleep, a very odd tiling occurs—most of the voluntary muscles in your body become paralyzed. Although your brain shows very rapid bursts of neural activity during REM sleep, your body is incapable of moving. REM sleep is accompanied by extensive muscular inhibition.  [br] On the part of an average sleeper, of sleep in cycles________.
选项 A、there is one stage
B、there are two stages
C、there are six stages
D、there are four stages
答案 D
解析 题目问普通人的睡眠有几个阶段。通读全文可知，本文第1段提到“进入第2、3阶段睡眠”以及 “进入最后一个阶段”，由此可知普通人的睡眠有4个阶段，故答案为D项。A项“1个阶段”、B项“2个阶段”和C项“6个阶段”均与文章内容不符，可排除。
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