单选题 Have you ever stayed up late.9 If so, you know that not getting enough sleep can leave you tired and grumpy (脾气暴躁的). Not sleeping enough can also make it harder to think clearly the next day.
Sleep experts have long known that getting a good night's sleep is important.
It helps kids perform their best during the day. A recent study shows that sleep helps improve problem-solving skills and creative(创造性) thinking.
For the study, two groups of volunteers answered a math problem. The group that slept for eight hours solved the problem correctly more often than the group that did not get enough sleep.
While you sleep, your brain is busy doing its" homework". It sorts out information from your day. Getting enough sleep each night can boost your brainpower. That will help you do your best in school. Experts say that, in return, can lead to better grades.

单选题 What is the best title for the text?
A. Too Much Sleep B. It's Homework Time
C. Sleep to Succeed D. Math Problems

【正确答案】 C

【答案解析】全文讲述了充足睡眠对人们的重要性：可以使人们心平气和，有助于提高解决问题的能力，有助于创造性思维的培养，有助于学业的成功。

单选题 What does your brain do while you are sleeping?
A. It improves problem-solving skills and creative thinking.
B. It helps you do your best in school.
C. It helps your brain sort out information from your day.
D. It has a good rest.

【正确答案】 C

【答案解析】由文章第五段的有关信息“While you sleep，your brain is busy doing its homework．It sorts out information from your day.”可知睡眠时大脑忙于处理白天所得到的信息，故[C]为正确答案。

单选题 What do the results of a recent sleep study show?
A. People who sleep enough are good at math.
B. Sleep is important for learning.
C. Too much sleep is good for your health.
D. Adults need more sleep than kids.

【正确答案】 B

【答案解析】由第三、四段可知，一项近期对睡眠的研究表明，那些经过充足睡眠的实验者比睡眠不足者解决问题的准确性更高，因此可以说“睡眠对于学习很重要”。这是一个相对概念，并不能因此就说睡眠充足者擅长数学了。故排除[A]；睡眠过多并不一定对身体有好处，故排除[C]。

单选题 The underlined word "boost” in the last paragraph means
A. watch B. stop C. lower D. increase

【正确答案】 D

【答案解析】如最后一段所述，睡眠时，大脑忙于“作业”——整理来自白天的信息。夜晚充足的睡眠可以帮助回复增加脑力，以便第二天更好地学习(和工作)。故[D]项正确。