歷年考研英語(yǔ)完型填空1995年

[00:05.20]1995 [00:07.51]Sleep is divided into periods of so-called REM sleep, [00:11.56]characterized by rapid eye movements and dreaming, [00:14.68]and longer periods of non-REM sleep. [00:17.50](1)Neither kind of sleep is at all well-understood, [00:20.52]but REM sleep is (2)assumed [00:22.44]to serve some restorative function of the brain. [00:25.57]The purpose of non-REM sleep is even more (3)mysterious. [00:29.20]The new experiments, such as [00:31.02]those (4)described for the first time [00:32.94]at a recent meeting of the Society [00:35.35]for Sleep Research in Minneapolis, [00:37.87]suggest fascinating explanations [00:40.09](5)for the purpose of non-REM sleep. [00:42.75]For example, it has long been known [00:45.59]that total sleep (6)deprivation is 100 percent fatal to rats, [00:50.14]yet, (7)upon examination of the dead bodies, [00:52.87]the animals look completely normal. [00:55.31]A researcher has now (8)cast light on the mystery [00:58.33]of why the aninlals die. [01:00.05]The rats (9)develop bacterial infections of the blood, [01:03.28](10)as if their immune systems [01:05.11]--the self-protecting mechanism against disease--had crashed.

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