9．Why can some people sleep through noises like a honking car or flushing toilet，while others are awakened by the lightest sound？
To find the answer，sleep researchers at Massachusetts General Hospital conducted an unusual study of 12self-described deep sleepers．After tests confirmed that the healthy volunteers were solid sleepers，they took part in a three-night study in the university's sleep laboratory．The participants spent the night in a big and comfortable room．But the room also included four speakers positioned near the top of the bed．
During the night，the deep sleepers were subjected to 14different recorded sounds，like street traffic，toilets flushing，an ice machine dispensing and an airplane flying overhead．Next door，the researchers monitored their sleep patterns and brain waves．
As expected，all of the participants slept relatively well，but there were differences in how they responded to the noisy interruptions．Some of the sleepers didn't wake up even when a sound was blasted at 70decibels （分貝）； others were awakened by sounds at 40or 50decibels．
The researchers discovered that the difference in a sleeper's reaction to noise could be predicted by the level of brain activity called"sleep spindles''．A sleep spindle is a burst of high-frequency brain activity coming from deep inside the brain during sleep．The source of the spindles is the thalamus，a part of the brain that sends sensory information to the rest of the cortex （皮層）．
Before the study，the Massachusetts researchers theorized （推理） that the spindles are the brain's way of preventing sensory information from passing through the thalamus and waking the rest of the brain during sleep．They found that the sleepers who experienced the most sleep spindles during the night were also the soundest sleepers and were least likely to be awakened by noise．
Scientists already know that most people become lighter sleepers with age，most likely because older people experience less"slow wave sleep''，which is the deepest stage of sleep．People also produce fewer sleep spindles as they age．But even when controlling for the stage of sleep a person was in，the number of sleep spindles still predicted their risk for awakening because of noise．
More research is needed，but the findings suggest that a better understanding of sleep spindles could lead to new behavioral or drug therapies for people with sleep disorders．For instance，future studies may try to determine whether diet，exercise or other behaviors may influence the number of sleep spindles a person produces during the night．
63．Some participants can sleep well through loud noises mainly becauseB．
A．their brains don't respond to outside noises
B．their brains react differently to noises
C．they adapt to the environment quickly
D．they don't pay attention to the monitors
64．Scientists believe that the key to affecting deep sleep isA．
A．sleep spindles B．stages of sleep C．sleep disorders D．sensory information
65．It can be learned from the passage thatB．
A．the older a deep sleeper becomes，the lighter his sleep must be
B．the more"slow wave sleep"one experiences，the deeper sleep one has
C．the more frequently a sleeper's brain works，the less information it sends
D．the deeper sleep people have，the more likely they will be awakened by noise
66．From the passage we can predictA．
A．more factors in influencing sleep spindles may be discovered
B．more solid sleepers will take part in relative experiments
C．sleep spindles will be applied to changing one's behaviors
D．deep sleepers will probably enjoy a more healthy life．
分析 本文講述了研究人員對(duì)人們?cè)跇O大的噪音下的睡眠問題，結(jié)果顯示大腦對(duì)噪音的反應(yīng)程度的不同會(huì)極大影響到睡眠情況．
解答 63．B 細(xì)節(jié)理解題．根據(jù)文章第四段的內(nèi)容As expected，all of the participants slept relatively well，but there were differences in how they responded to the noisy interruptions 參加者們都睡的著，但他們的區(qū)別在于對(duì)噪音的反應(yīng)是不一樣的，故答案選B．
64．A 細(xì)節(jié)理解題．根據(jù)文章第五段的內(nèi)容They found that the sleepers who experienced the most sleep spindles during the night were also the soundest sleepers and were least likely to be awakened by noise．可知，睡眠紡錘復(fù)合波會(huì)是深度睡眠的關(guān)鍵，故答案為A．
65．B 推理判斷題．根據(jù)Scientists already know that most people become lighter sleepers with age，most likely because older people experience less"slow wave sleep''，which is the deepest stage of sleep 科學(xué)家 研究發(fā)現(xiàn)人們會(huì)隨著年齡的增長(zhǎng)而睡眠變淺，那是因?yàn)槔先藭?huì)經(jīng)歷更少的"slow wave sleep''，而這種狀態(tài)正是睡眠的最深狀態(tài)，由此可判斷B為正確選項(xiàng)．
66．A 推理判斷題． 根據(jù)文章最后一段總結(jié)可知，研究人員會(huì)對(duì)飲食、鍛煉以及其他進(jìn)行研究，以得知其是否會(huì)對(duì)sleep spindles 有影響，再結(jié)合選項(xiàng)，故選A．
點(diǎn)評(píng) 本文是健康環(huán)保類閱讀理解．做這類題材閱讀理解時(shí)要求考生對(duì)文章通讀一遍，做題時(shí)結(jié)合原文和題目有針對(duì)性的找出相關(guān)語(yǔ)句進(jìn)行仔細(xì)分析，結(jié)合選項(xiàng)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(cè)，一定要做到有理有據(jù)．
