题目内容
Why is that many teenagers have energy to play computer games until late at night， but can't find the energy to get out of bed in time for school？ According to a new report， today's teenagers are getting so little sleep but their health is in danger．
This raises serious questions about whether being short of sleep is influencing children's ability to pay attention at school． Research has shown that losing even just half an hour's sleep at night can have deep influences on how children perform the next day．
So why aren't teenagers getting enough sleep？Some experts suggest that televisions， computers and mobile phones in children's bedrooms may cause problems．Instead of reading a book at bedtime，children are playing computer games，surfing the web，sending messages， or watching television．As these new pre-sleep activities have become more common，more traditional ones such as reading have become less，Dr．Luci Wiggs，a researcher at Oxford
University's Section of Child and Adolescent Psychiatry said，“One of the problems with these pre-sleep activities is that they do not have clear start and end times which leads to being short of sleep．”
Research has shown that teenagers have different sleep patterns from adults．Human bodies produce melatonin（褪黑激素）to help fall asleep． Most adults start to produce melatonin at
about 10 pm，while teenagers only begin to produce it three hours later．It is possible that this delay in melatonin production is caused by the behaviors of teenagers such as playing with phones late at night．
Problems about sleep- who needs how much and when -are usually connected to students' achievements． But modern brain researchers say it is time that more schools wake up to both biological and social facts and make a better timetable for their teenager students．
1.What can we learn from Paragraph 2？
A.It's very common for teenagers to have less sleep．
B.It doesn't matter if children sleep half an hour less．
C.Being short of sleep has influence on children．
D.A good night sleep at weekends helps children study well．
2.According to Dr．Luci Wiggs，．
A.too many pre-sleep activities take up teenagers' sleeping time．
B.playing computer games before bedtimes does harm to health．
C.fewer and fewer children read books at bedtime today．
D.teenagers shouldn't watch TV before they go to sleep．
3.What does the underlined word 'delay' mean？
A.Rushing． B.Changing． C.Putting off． D.Cutting off．
4.What can we infer from Paragraphs 4 and 5？
A.Schools need to offer more biology classes．
B.Teenagers may be kept awake by themselves．
C.Melatonin influences teenagers' achievements．
D.It's necessary for schools to start classes later．
5.Which can be the best title for this passage？
A.Wake Up Sleeping Teenagers
B.Let Sleeping Teenagers Lie
C.Keep Away From Electronic Products
D.How to Sleep
