4．I've often wondered how exactly sleep，or lack of it，can have such an awful effect on our bodies and，guess what，how much we sleep switches good genes（基因） on and had genes off．
In the first half of 2013，the Sleep Research Centre at the University of Surrey found a direct link between hours spent sleeping and genes．Every cell in our bodies carries genetic instructions in our DNA that act as a kind of operating handbook．However，each cell only"reads"the part of this handbook it needs at any given moment．
Can sleep affect how a gene reads instructions？It's a question asked by Professor Derk-Jan Dijk at the University of Surrey．He set up an experiment and asked his volunteers to spend a week sleeping around seven and a half hours to eight hours a night and the next sleeping six and a half to seven hours．
Blood samples were taken each week to compare which genes in blood cells were being used during the long and short nights．The results were rather surprising．Several hundred genes changed in the amount they were being used，including some that are linked to heart disease，cancer，and Type 2diabetes．Genes to do with cell repair and replacement were used much less．
Sleep restriction（six and a half to seven hours a night） changed 380genes．Of these，220genes were down regulated （their power was increased）．Those affected included body-clock genes which are linked to diabetes（糖尿病）．One of the most downgraded genes is that which has a role in controlling insulin（胰島素） and is linked to diabetes and insomnia（失眠）．The most upgraded gene is linked to heart disease．
So changing sleep by tiny amounts can upgrade or downgrade genes that can influence our health and the diseases we suffer from when we sleep too little．
The important message is that getting close to eight hours of sleep a night can make a dramatic difference to our health in just a few days through the way it looks after our genes．
28．What kind of relation is directly discussed in the passage？A
A．Sleeping hours and changes of genes．
B．Sleeping hours and diseases．
C．Changes of genes and diseases．
D．Genes and health．
29．What can we learn about Professor Derk-Jan Kijk's experiment？C
A．The experiment was carried out to find the answer to how genes affect sleep．
B．The experiment took a period of more than two weeks to reach a conclusion．
C．His volunteers were divided into two groups with two different sleeping patterns．
D．Blood samples of the volunteers were checked afterwards to decide how many genes changed in sleeping．
30．Which of the following may be concluded from the passage？C
A．The experiment was performed at the University of Surrey in early 2013．
B．Body-clock genes are associated with heart disease，cancer and Type 2diabetes．
C．Sleep restrictions may contribute to disease like diabetes，insomnia，and heart disease．
D.7.5-8hours'sleep pattern makes little difference compared with 6.5-7hours'sleep pattern．
31．Which of the following can be inferred from the findings of the sleep research？D
A．When there is a sleep restriction，genes to do with cell repair and replacement function less．
B．In a sleep，several hundred genes change in the amount．The more changes，the worse results．
C．When genes are up regulated，they do good to health； when genes are down regulated，they do harm to health．
D．Eight hours of sleep a day can be beneficial to our health in that it looks after our genes．
分析 本文介紹了睡眠時間對身體健康的影響．
解答 28．A，主旨大意題，本文主要講述的是睡眠時間與人體內(nèi)基因在睡眠狀態(tài)下產(chǎn)生變化之間的關(guān)系，故答案為A．
29．C，推理判斷題，根據(jù)句子 found a direct link between hours spent sleeping and genes可知，實驗主要目的是發(fā)現(xiàn)睡眠時間長短對人體基因變化的影響，而不是基因影響睡眠，故A不正確．實驗是分兩組進行，志愿者進行兩種睡眠時間的測試，故選C正確．
30．C，推理判斷題．根據(jù)句子Those affected included body-clock genes which are linked to diabetes（糖尿�。甇ne of the most downgraded genes is that which has a role in controlling insulin（胰島素） and is linked to diabetes and insomnia（失眠）．The most upgraded gene is linked to heart disease．可知，睡眠時間不足可能引起人體基因的變化，而這些人體基因變化是導(dǎo)致人體某些病癥的產(chǎn)生，如糖尿病，失眠癥，心臟病的產(chǎn)生等，故選C正確．
31．D，推理判斷題．根據(jù)文章第七段的描述The important message is that getting close to eight hours of sleep a night can make a dramatic difference to our health in just a few days through the way it looks after our genes，8個小時的睡眠模式對人體是非常有益的，因為這樣的睡眠時間能很好地照料決定人體健康方面的基因，因此D項正確．
點評 解答任務(wù)型閱讀理解題，首先對原文材料迅速瀏覽，掌握全文的主旨大意．因為閱讀理解題一般沒有標(biāo)題，所以，速讀全文，抓住中心主旨很有必要，在速讀的過程中，應(yīng)盡可能多地捕獲信息材料．其次，細讀題材，各個擊破．掌握全文的大意之后，細細閱讀每篇材料后的問題，弄清每題要求后，帶著問題，再回到原文中去尋找、捕獲有關(guān)信息．最后，要善于抓住每段的主題句，閱讀時，要有較強的針對性．對于捕獲到的信息，要做認(rèn)真分析，仔細推敲，理解透徹，只有這樣，針對題目要求，才能做到穩(wěn)、準(zhǔn)．
