Question

             B ★★★★☆ !

    It is 7 am and the alarm is going off. You know you have to get out of bed to catch the school bus. But the strong wish to bury yourself in the bed is ever so strong. Does it sound familiar?

    During adolescence(青春期) ，the body goes through many changes including changes in sleep patterns. Researchers have found that though : adolescents need as much as 9.5 hours of sleep a day they go to bed later and later with each passing year.

    In fact,the sleep cycle shifts later by as much as ： 12 to 18 minutes each year between the ages of 10 and 20!So by the time a 10-year-old who sleeps at 8 pm ' grows to be 17 or 18,his body naturally wants to stay up till 10:30 or 11 pm.

    According to researchers,this is because of a hormone called melatonin(褪黑素) that is produced by the pineal gland — a tiny structure deep inside the brain. Melatonin controls a body's natural d?y-night patterns. It causes a person tò become sleepy by lowering his body's (体核温度) .It is produced much later in the evening and continues to increase throughout the night. This makes it difficult for teens to fall asleep earlier as they did in their younger years.

    Sleep is food for the brain. During sleep,important bodily functions and brain activities happen. Not sleeping can be harmful and even deadly 一 especially for those 'who drive. A slow brain makes it difficult to concentrafe. and can affect grades at school.

    The American Association of Pediatrics (AAP) suggests that letting teens sleep in during school days can lead to overall b?peí?ts for them,since children who are suffering from a lack of sleep are more likely to suffer from anxiety,have traffic accidents and perform poorly at schools. In fact,AAP advises that middle and high schools should start later 一 not before 8:30 am. But a later Start time means a later end time too. Will that affect after-school activities?

5. Researchers have found that teens .

   A. should go to bed at 10:00 or 11 pm

   B. will fall asleep later as they grow older 

    C. are unwilling to take the school bus

   D. should sleep more than 9;5 hours one day

6. According to Paragraph 4 ,what causes some teens to be sleepy?

   A. Melatonin. 

    B. After-school activities,

    C. Sleep patterns. 

    D. The core temperature.

7. The AAP believes that .

   A. teens,health is threatened by lack of activities

   B. scho?ls should end earlier than before

    C. lack of sleep affects teens’after-school  activities   

    D. schools should put off their start time

8. The text is mainly concerned with

   A. sleep hours and teenagers' brain

   B. sleep hours and class behavior

    C. effective ways to improve teens’ sleep

   D. a comparison of sleeping more and sleeping less

Answer 1

5. B 6.A 7.D 8. A

B篇本文主要说明了睡眠和青少年大脑健康的关系，建议学校延迟早上开始上课的时间。

5. B细节理解题。由第二段中的they go to bed later and later with each passing year 可知，随着年 龄的增长，青少年睡得越来越晚。

6.A.细节理解题。由第四段中的Melatonin controls a body's natural day-night patterns. It causes a person to become sleepy by lowering his body's core temperature可知，褪黑素通过降低 一个人的体核温度导致他恹恹欲睡。

7.D.细节理解题。由最后一段中的In fact,AAP advises that middle and high,schools should start later 一 not before 8:30 am 可知，AAP 建议学校 8:30以后上课，即推迟早上开始上课的时间。

8. A. 主旨大意题。通读全文可知,本文主要说明了睡眠和青少年大脑健康的关系。