16．Ellen Sims is an 18-year-old college student．She has an important history exam tomorrow morning．Ellen is going to study all night．She is not going to sleep at all．Many college students，like Ellen，do this often．They think that they can study all night．And they think that in the morning，they will remember everything that they studied the night before，Ellen thinks that this is a good way to study，but many doctors disagree．They say that sleep is very important for memory and brain development．
Scientists at Harvard Medical School in the US studied sleep and memory．They studied 24people．First，they asked the people to look at a picture and remember it．At night，they put the people in two groups of 12．Group One went to sleep．Group Two did not．A few days later，the scientists showed some pictures to both groups．They asked the people to find the picture they saw before．The people in Group One did well．But the people in Group Two did not do well．It wasn't easy for them to remember the picture．What happened？Scientists say that sleep helps our memory．After we learn something new，sleep helps us remember it．And when we don't sleep，we can forget new things．
Scientists say that many teenagers，like Ellen，sleep too little．They go to school and they work，too．They also spend time with their friends．They are always busy and they think that sleep doesn't matter．But scientists say the brains of teenagers are still developing，and sleep is a very important part of the development．When teens sleep less than six hours，they can't think clearly．That is not very helpful for a student who is taking an exam．
65．Is Ellen going to study all night before the history exam？Yes，she is
66．Who studied sleep and memory？Scientists at Harvard Medical School in the US
67．How many people were there in each group for this study？12 people
68．Why did Group One remember the picture better？Because sleep helped their memory．/Because sleep helped them remember things
69．What can we learn from the passage？The brains of teenagers are still developing，and sleep is a very important part of the development．/Sleep is very important for memory and brain development．
分析 这篇短文讲的是有些人认为熬夜学习对记忆有帮助，其实科学研究证明并不是这样，尤其青少年更要有充足的睡眠，这一点非常重要．
解答 65．Yes，she is．细节理解题．根据Ellen is going to study all night．She is not going to sleep at all可知爱伦打算在历史考试前通宵学习，故答案为：Yes，she is．
66．Scientists at Harvard Medical School in the US细节理解题．根据Scientists at Harvard Medical School in the US studied sleep and memory可知美国哈佛医学院的科学家研究睡眠和记忆，故答案为：Scientists at Harvard Medical School in the US．
67.12 people．细节理解题．根据they put the people in two groups of 12可知每个团队有12个人，故答案为：12 people．
68．Because sleep helped their memory．/Because sleep helped them remember things．细节理解题．根据Group One went to sleep和Scientists say that sleep helps our memory可知一组是因为有充足的睡眠，这帮助记忆，故答案为：Because sleep helped their memory．/Because sleep helped them remember things．
69．The brains of teenagers are still developing，and sleep is a very important part of the development．/Sleep is very important for memory and brain development．主旨大意题．根据文章内容But scientists say the brains of teenagers are still developing，and sleep is a very important part of the development．可知从文中我们可以了解到青少年的大脑还在发育，睡眠是成长的一个重要部分，故答案为：The brains of teenagers are still developing，and sleep is a very important part of the development．/Sleep is very important for memory and brain development．
点评 做题时首先要仔细阅读短文，掌握大意，然后结合具体的题目，找出相关信息，就可以确定正确答案．
