9．When US student Olivia Priedeman，17，woke up one morning，she thought she had had a dream about making plan with a friend．
But it wasn't a dream．Her phone showed that during the night，Prideman had read a text message from her friend．
She did it while she was fast asleep．
Reading and sending text messages while asleep-called"sleep texting"-is an unusual sleep behaviour，similar to sleepwalking．It's also a growing concern（关心的事） among doctors：young people can't live without their cell phones．
Research shows one in three teenagers sends more than 100text messages a day．And at least four out of five teenagers said they sleep with their phone on or near their bed．
Elizabeth Dowdell，a professor at Villanova University in Pennsylvania，has studied sleeping texting．She said that having a phone nearby all night is a big part of the problem．
Andrew Stiehm，a sleep medicine expert with Allina Health in Minnesota，explains how sleep texting happens this way．It's possible for the part of the brain that controls motor skills （动作技能） to wake up，while the part of the brain that controls memory and judgment（判断） may be still asleep．That's why some people can perform basic movements---such as walking，talking，texting or even driving-while they're sleeping．
Some of Dowdell's students said that they're troubled by their nighttime texting behavior．But because sleep texting is unconscious（无意识的），it's a difficult habit to break．Dowdell said she knows of some students who wear socks on their hands to keep themselves from texting．
Marjorie Hogan，a doctor at Hennepin County Medical Center in Minneapolis，Minnesota，suggests keeping all electronic devices（电子设备） outside the bedroom at certain times．
42．What happened to Olivia Priedeman？D
A．She sleepwalked to a friend's house．
B．She dreamed of making plans with a friend．
C．She phoned one of her friends during the night．
D．She read a text message from her friend while asleep．
43．How does sleep texting happen？B
A．Some parts of the body are out of control during sleep．
B．The brain part in control of motor skills wakes up during sleep．
C．The brain part in control of judgment stays awake during sleep．
D．The brain part in control of memory becomes unconscious during sleep．
44．What does doctor Hogan suggest people who sleep text do？C
A．Stop texting during the daytime．
B．Take some medicine to control the behavior．
C．Keep their phones out of their bedrooms while they sleep．
D．Wear socks on their hands to stop themselves from texting．
45．Which of the following statements about sleep texting is TRUE？A
A．Sleep texting can reduce the quality of one's sleep．
B．It's easy to give up a sleep texting habit．
C．Sleep texting does more harm to one's health than sleepwalking．
D．One in three teenagers has a sleep texting habit．
分析 这篇短文主要介绍了睡眠短信类似于梦游"是一种不寻常的睡眠行为．形成这种行为的原因是频繁的使用手机并发信息．专家说在睡眠中大脑控制运动技能的一部分是醒着的而大脑的控制记忆和判断一部分可能还在睡觉．所以出现了睡眠短信这一现象．
解答 答案：42．D 细节理解题．根据第二段句子Her phone showed that during the night，Priedeman had read a text message from her friend．She did it while she was fast asleep．可知那不是一个梦．她的手机显示，在夜间她读过从她的朋友发来的短信．她睡着的时候做的这件事．故选D
43．B 细节理解题．根据倒数第三段句子It's possible for the part of the brain that controls motor skills （动作技能） to wake up，很可能是控制大脑运动神经的部分醒了，可知控制运动技能的大脑部分在睡眠中醒来．故选B．
44．C 细节理解题．根据最后一段句子keeping all electronic devices outside the bedroom at certain times．建议把所有电子设备在特定时间放在卧室外，可知医生建议在睡觉时将所有电子设备移到卧室以外．即睡觉时把手机放在卧室外，故选C．
45．A 细节判断题．根据倒数第二段句子But because sleep texting is unconscious（无意识的），it's a difficult habit to break．但是因为睡眠短信是无意识的，这是一个难以打破的习惯．可知B错误；第五段句子One in three teenagers sends more than 100 text messages a day，三分之一的青少年每天发送超过100条短信，可知D错误．第四段句子 sleep texting"-is an unusual sleep behaviour，similar to sleepwalking．可知C错误．倒数第二段句子Some of Dowdell's students said that they're troubled by their nighttime texting behavior．Dowdell的一些学生说他们被夜间短信的行为所困扰．可知睡眠短信可以减少一个人的睡眠质量．故选A．
点评 在通读全文的基础上，根据全文大意，展开逻辑思维，瞻前顾后，认真观察选项，仔细推敲，确定最佳答案．
