【正确答案】lazy

【答案解析】[听力原文] How Much Sleep Do We Need Today, we are going to talk about how much sleep we need. Tired? We all know the feeling. Irritable, groggy and exceptionally lazy. Chances are, you didn't sleep enough last night, or the past few nights. But, what exactly is enough sleep? And more importantly, can you ever catch up on it? Well, the very function of sleep is still debated by scientists. We do know that it is necessary to function efficiently and productively. After all, we spend 24 years of our lifetime sleeping, so it'd better be important. Researchers have tested how much is required each night by assigning groups of people to 4, 6 and 8 hours of sleep over extended periods of time. After 14. days, those people with 8 hours of sleep exhibited fewer attention lapses or cognitive issues. However, those with 6 or 4 hours of sleep showed a steady decline. In fact, after only 2 weeks, the 6-hour group showed a similar reaction time to a person with the blood alcohol concentration of 0.11% which is considered legally drunk. The 4-hour sleepers suffered even more occasionally falling asleep during their cognitive tests. In both groups, brain functions decrease day by day, almost linearly, with no sign of leveling off, and scientists have dubbed this cumulative effect as 'sleep Dept'. So, can we recover from it? After a night or two of little sleep, the study shows that the body and brain can fully recover with a few nights of good sleep. However, with long-term sleep deprivation on the scale of weeks to months, the recovery of cognitive function is much slower, requiring many more nights of quality sleep. On the time scale of months to years, it's unknown whether brain function could be fully repaired, or if it causes permanent damage, paradoxically, with chronic sleep deprivation. Your sleepiness or how tired you feel does eventually level off, meaning that you become less and less aware of your objective impairment over time. So, how long should you sleep? Most studies tend to show that 7-8 hours of sleep is average ideal for humans. Apart from the cognitive issues, individuals who consistently sleep less than 7 hours a night have an increased risk of heart disease, obesity and diabetes, not to mention a 12%higher risk of death. On the flip side, studies have shown that while sleeping more than 8 hours does not impair brain function, it also carries an increased risk of heart disease, obesity and diabetes, and a 30% increase risk of mortality. So, too much sleep may also be a bad thing. But variation most certainly exists, and our genes play a large role. In fact, individuals genuinely unaffected by only 6 hours of sleep were found to have a mutation of a specific gene. When scientists genetically engineered mice to express this gene, they were able to stay awake for an extra of 1.2 hours than normal mice. It turns out these short-time sleepers have more biologically intense sleep sessions than an average person. [考点] 本题出题点在讲座开头的并列信息处。 从题干处的标题The result of lack of sleep可知，此处考查的是缺乏睡眠导致的结果。讲座中提到Irritable, groggy and exceptionally lazy. Chances are, you didn't sleep enough last night, or the past few nights. 故得答案lazy。

【正确答案】similarly

【答案解析】[考点] 本题出题点在对比处。 从题干标题Experiment可知，此处考查的内容与实验有关。再根据题干处的Sleeping time: 6 hours可知，此处是针对睡眠时长为6小时的人的实验结果，讲座中提到the 6-hour group showed a similar reaction time to a person with the blood alcohol concentration of 0.11% which is considered legally drunk. (睡眠时长为6小时的这一小组里的人，与达到法定醉酒标准——血液酒精浓度为0.11%的人反应时间相似。)可知，睡了6个小时的人与醉酒的人反应相似，故得答案similarly。

【正确答案】even more occasionally

【答案解析】[考点] 本题出题点在数字信息处。 此处考查的信息仍然与实验有关。根据题干处的Sleeping time: 4 hours可知，此处说的是针对睡眠时长为4小时的人的实验结果，讲座中提到The 4-hour sleepers suffered even more occasionally falling asleep during their cognitive tests. (睡眠时长为4小时的人在认知测试中偶尔会睡着的次数甚至更多。)故得答案even more occasionally。

【正确答案】good/sound/quality

【答案解析】[考点] 本题出题点在重要信息处(the study shows)。 从题干处的标题How to recover?可知，讲座第三部分主要讲的是如何从睡眠不足的情况恢复身体健康。根据题干上方的short-term sleep deprivation可知，此处是指短期睡眠不足的人的恢复方法，讲座中提到the study shows that the body and brain can fully recover with a few nights of good sleep. 可知，人们需要连续睡几晚好觉才能恢复，故得答案good或sound或quality。

【正确答案】longer

【答案解析】[考点] 本题出题点在转折处(However)。 此处还是讲如何从睡眠不足中恢复的问题。根据题干上方的Weeks-to-months sleep deprivation可知，此处是睡眠不足达几周或几个月的人的恢复方法，讲座中提到However, with long-term sleep deprivation on the scale of weeks to months, the recovery of cognitive function is much slower, requiring many more nights of quality sleep. (然而，睡眠不足达几周到几个月的人，认知功能的恢复要慢得多，需要多睡几晚好觉。)从这句话可以了解到这类人需要更长的时间来恢复，故得答案longer。

【正确答案】unknown

【答案解析】[考点] 本题出题点在否定处(it's unknown whether)。 此处仍然考查如何恢复认知功能的问题。根据题干上方的Months-to-years sleep deprivation可知，此处是睡眠不足达几个月到几年的人的恢复方法，讲座中提到On the time scale of months to years, it's unknown whether brain function could be fully repaired(睡眠不足达几个月到几年的人，大脑功能是否能完全得到修复尚不可知)，故得答案unknown。

【正确答案】7-8

【答案解析】[考点] 本题出题点在重要细节(Most studies lend to show that)和数字信息处 从题干处的大标题How much sleep do we need?可知，此处考查人们需要的睡眠时长。根据题干上方的Ideal time可知，此处是指理想的睡眠时长，讲座中提到Most studies tend to show that 7-8 hours of sleep is average ideal for humans. 故得答案7-8。

【正确答案】obesity

【答案解析】[考点] 本题出题点在重要细节处。 本题还是与睡眠时长有关，根据题干上方的Sleep less than 7 hours可知，此处考查的是睡眠时长少于7小时可能造成的影响。讲座中提到individuals who consistently sleep less than 7 hours a night have an increased risk of heart disease, obesity and diabetes. 故得答案obesity。

【正确答案】12%

【答案解析】[考点] 本题出题点在数字信息处。 本题仍然考查睡眠时长少于7个小时的危害。空格后是higher risk of death(更高的死亡风险)，讲座中提到not to mention a 12% higher risk of death。故得答案12%。

【正确答案】Genes

【答案解析】[考点] 本题出题点在转折处(But)。 题干为：______对人们所需睡眠时长的不同起了作用。讲座中提到But variation most certainly exists, and our genes play a large role. 故得答案Genes。