2．Sleep is just as important as diet and exercise，and not getting enough sleep can lead to obesity，heart trouble and other health problems．Now scientists are adding more wake-up call to that list：lack of sleep damages the brain．
People who regularly have trouble falling asleep and staying asleep （one study drew the line at 6.8hours ） show changes in brain-----actual shrinking（縮�。琲n some cases---in area important for memory and problem solving．
"We've always believed that we can take the weekend to catch up and be fine，"says Sigrid Veasey，a researcher in University of Pennsylvania，but that may not be the case．When she stopped mice from sleeping for 3days，they lost 25% to 30% of the neurons （神經(jīng)元） important for focused attention----and these remaining were damaged．What's more，these brain cells never grew again．
Clearly，something important is happening while we sleep，but exactly what sleep does for the brain has been a mystery．That's why scientists got excited when researchers at the university of Rochester Medical Center recently offered a new theory．While observing the brains of sleeping mice，they discovered a kind of brain-cleaning system that clears away neural waste，the buildup of which is connected with Alzheimer's．
In another study，young healthy people whose sleep was limited to 7hours per night for one week showed damaged brain function．Scarier is that with long-lasting short sleep，you may feel fully rested．When study subjects were limited to 4hours of sleep for 5days，they reported feeling very tired following the first night but they didn't get any sleepier after that．
What's more，a 15，000-person study found that getting an average of less than 5hours of sleep per night for several years resulted in a decrease in memory performance equal to the brain aging 2years．
Have we persuaded you to turn in early tonight？Excellent．
32．The text is mainly aboutA．
A．how lack of sleep damages our brain．
B．why we feel rested without enough sleep．
C．how much sleep we should get every day．
D．Why we have trouble falling asleep sometimes．
33．Sigrid Veasey's research shows thatB
A．lack of sleep doesn't affect our attention．
B．damaged brain cells can not recover．
C．sleeping on weekends can make up for lost sleep．
D．most neurons will die if we sleep poorly for 3days．
34．According to paragraph 5，after several days of short sleep people may feelC．
A．tired
B．sleepy
C．energetic
D．a(chǎn)ngry
35．According to the 15，000-person study，lack of sleep may causeD．
A．heart trouble
B．obesity
C．death
D．memory loss．
分析 研究表明缺少睡眠會導(dǎo)致肥胖，心臟病和其它的疾病．現(xiàn)在科學(xué)家又發(fā)現(xiàn)缺少睡眠會損害大腦．
解答 32．A考查主旨大意題．根據(jù)第一段內(nèi)容Now scientists are adding more wake-up call to that list：lack of sleep damages the brain．可知本文說的是缺少睡眠會損害大腦．故選A．
33．B 考查細(xì)節(jié)理解題．根據(jù)第二段內(nèi)容When she stopped mice from sleeping for 3 days，they lost 25% to 30% of the neurons （神經(jīng)元） important for focused attention----and these remaining were damaged．What's more，these brain cells never grew again．可知他讓老鼠3天不睡覺，老鼠的神經(jīng)元就會減少25%到30%，而且腦細(xì)胞再也不會生長了．故選B．
34．C考查推理判斷題．根據(jù)第五段內(nèi)容Scarier is that with long-lasting short sleep，you may feel fully rested．"可知經(jīng)歷長時間的少睡眠后，人仍然會感到fully rested，即energetic（精力充沛的）．故選C．
35．D考查細(xì)節(jié)理解題．根據(jù)最后一段內(nèi)容What's more，a 15，000-person study found that getting an average of less than 5 hours of sleep per night for several years resulted in a decrease in memory performance equal to the brain aging 2 years．可知每晚平均睡眠少于5小時，持續(xù)幾年會導(dǎo)致記憶力降低，相當(dāng)于大腦老化了2年．故選D．
點評 本文是科教類閱讀理解．做這類題材閱讀理解時要求考生對文章通讀一遍，做題時結(jié)合原文和題目有針對性的找出相關(guān)語句進(jìn)行仔細(xì)分析，結(jié)合選項選出正確答案．推理判斷題也是要在抓住關(guān)鍵句子的基礎(chǔ)上合理的分析才能得出正確答案，切忌胡亂猜測，一定要做到有理有據(jù)
