新概念英语第四册第19课:The stuff of dreams

Lesson 19   The stuff of dreams话说梦的本质      First listen and then answer the following question.      听录音，然后回答以下问题。      What is going on when a person experiences rapid eye-movements during sleep?        It is fairly clear that sleeping period must have some function, and because there is so much of it the function would seem to e important. Speculations about is nature have been going on for literally thousands of years, and one odd finding that makes the problem puzzling is that it looks very much as if sleeping is not simply a matter of giving the body a rest. 'Rest', in terms of muscle relaxation and so on, can be achieved by a brief period lying, or even sitting down. The body's tissues are self-repairing and self-restoring to a degree, and function best when more or less continuously active. In fact a basic amount of movement occurs during sleep which is specifically concerned with preventing muscle inactivity.      很清楚，睡眠必然具有某种作用。睡眠占去那么多时间，所以其作用似乎还是很重要。人们对睡眠作用的种种猜测，确实有数千年之久。一项使人对这个问题感到困 惑的奇怪的发现是，睡眠在很大程度似乎并不仅仅是为了使身体得到休息。“休息”，从使肌肉得到放松等方面来看，只要稍微躺一躺，甚至坐一坐就能达到。人体 组织在一定程度上有自我修补和自我恢复的能力，有张有弛地连续活动时，其功能最佳