A
(2020·广州市调研测试)Sleep，considered a luxury by many，is essential for a person's wellbeing.Researchers have found that insufficient sleep and tiredness increase a person's risk of developing severe medical conditions，such as obesity(肥胖症)，high blood sugar levels，and heart disease.Now，a new study has found that getting sufficient sleep is also the key to improving academic performance.
Jeffrey Gross，the university science professor who led the research，was not trying to find the relationship between sleep and grades when he handed out smartwatches to the 100 students in his chemistry class.Instead，the professor hoped the wristworn devices，which track a person's physical activity，would show a connection between exercise and academic achievements.
While Gross's data showed no relationship between these two factors，the study found something surprising.As the researchers were analyzing their data，they noticed that there was a linear(线性的) relationship between the average amount of sleep the students got and their results in the course's 11 quizzes，three midterm tests，and the final exam.
Even more interesting，it was not sufficient for students to just head to bed early the night before a test.Instead，it's the sleep you get during the days when learning is happening that matters most.
When students went to bed each night was similarly important.Those who went to bed in the early hours of the morning performed poorly，even if the total sleep time was the same as a higherperforming student.“When you go to bed matters，” Gross says.“If you go to bed at 10，or 12，or 1 at night，and sleep for seven hours，your performance is the same.But if you go to bed after 2，your performance starts to go down even if you get the same seven hours' sleep.So，quantity isn't everything.”
Perhaps the most interesting was the huge impact that small differences in sleep patterns had on the students' grades.The overall course grades of students averaging six and a half hours of sleep each night were 25% lower than students who averaged just one hour more sleep.Similarly，students who varied their bedtime by even one hour each night had grades that dropped 45% below those with more regular bedtime.
Who knew getting straight A's just required some extra sleep?
【语篇解读】 一项新的研究发现，每天在恰当的时间段内进行充足的睡眠是提高学业成绩的关键。
1．Based on his original objective，which best describes Professor Gross's research findings?
A．Accidental. B．Complete.
C．Convincing. D．Doubtful.
A [细节理解题。根据第二段的内容以及第三段第一句“While Gross's data showed no relationship between these two factors，the study found something surprising”可知，Gross给自己班里的100名学生分发智能手表是打算研究运动与学业成绩之间的联系，但是Gross搜集到的数据没有表明二者之间的联系，不过该研究有意外的发现。故选A。]
2．Who were the people taking part in the study?
A．Middle school chemistry students.
B．Volunteers from different universities.
C．Professor Gross's own students.
D．University student athletes.
C [细节理解题。根据第二段第一句中的“he handed out smartwatches to the 100 students in his chemistry class”可知，参加研究的是Gross自己的学生。故选C。]
3．How did Professor Gross's team measure students' academic performance?
A．Making the students wear special watches.
B．Using students' university entrance test results.
C．Giving the students regular quizzes after class.
D．Using the students' normal test and quiz grades.
D [细节理解题。根据第三段第二句“As the researchers were analyzing their data...their results in the course's 11 quizzes, three midterm tests，and the final exam”可知，当研究人员分析他们的数据时，他们注意到学生的平均睡眠时间与他们在这门课的11次小测验、3次期中考试和期末考试中的成绩之间存在线性关系。由此可知，Gross教授的团队是使用学生平常的测试与小测验成绩来衡量学生的学业表现的。故选D。]
4．Based on the study's findings，who is likely to perform best academically?
A．A student who has a good night's sleep the night before an important test.
B．A student whose normal bedtime varies between 9 p．m.and 12 p．m.
C．A student who sleeps from 11 p．m.to 6 a．m.each day.
D．A student who sleeps for a total of 7 hours each night.
C [推理判断题。根据第五段的内容可知，什么时候去睡觉很重要，如果你晚上10点、12点或1点睡觉，睡7个小时，你的表现是一样的；但是如果你在2点以后睡觉，即使你同样睡了7个小时，你的表现也会开始下降。且根据第六段最后一句可知，有规律的就寝时间也很重要。由此可推知，每天从晚上11点睡到早上6点的学生，其学业表现可能最好。故选C。]
【干扰项分析】 根据第四段第一句中的“it was not sufficient...before a test”可知，A项错误。
