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 lo ...