单选题 We've all been there. You wake up in the middle of the night and grab your smartphone to check the time—it's 3 a. m.—and see an alert. Before you know it, you fall down a rabbit hole of e-mail and Twitter. Sleep? Forget it. Well, I've found a $7 solution: an old-fashioned alarm clock. My smartphone has been banished from the bedroom.
'It's a very slippery slope, once you've picked up your phone, to see what time it is, to checking your e-mail, to lying awake with anxiety,' said Dr. David M. Claman, director of the Sleep Disorders Centre at the University of California San Francisco Medical Centre. 'If you wake up in the middle of the night and check your phone, you will inevitably get frustrated and worried by something you've seen, leading your body to tense up.' Then it's game over. You're tossing and turning, thinking about an e-mail, a text or a meeting in six hours. All these sleep interruptions lead to work problems. A 2011 study by the American Academy of Sleep Medicine found that insomnia costs $2280 in lost productivity per American worker every year. That adds up to $63 billion a year for the nation.
The draw of the smartphone is understandable. The alarm clock is a free feature. It's also incredibly convenient—who doesn't like being able to speak to their phone and say, 'Wake me up at 7 a.m.'? Device makers are helping the trend along and hoping these figures rise. Most new alarm clocks made today are designed to be married to a smartphone. This goes against years of research showing that screens, in any capacity, do everything but help us fall asleep. In 2012, the American Medical Association's Council on Science and Public Health said that 'exposure to excessive light at night, including extended use of various electronic media, can disrupt sleep or exacerbate (使恶化) sleep disorders.'
Sleep researchers say that looking at a blue light, which is produced by smartphone and tablet screens, sets off brain receptors that are designed to keep us awake and interferes with circadian (生理节奏的) sleep patterns. Experimental research has found that if people use a tablet for up to two hours before bed, it takes an extra hour to fall asleep.
Orfeu M. Buxton, a neuroscientist and assistant professor in the division of sleep medicine at Harvard Medical School, said the phone in the bedroom could set off what he called 'threat alertness,' which is a type of anxiety that keeps you awake. 'This means that you're never off, you're always watchful, which is a hallmark to insomnia (失眠),' he said.

单选题 What is the initial reason that some people wake up in the middle of the night?

【正确答案】 D

【答案解析】细节辨认题。由第一段第二、三句可知，人们半夜醒来，拿起智能手机看时间，然后看到一条提醒，然后稀里糊涂地就刷起邮件和Twitter来。由此可以得知，造成人们半夜睡不着的最初原因是人们想看看时间而已，故答案为C。A“他们失眠了”，这并不是导致人们半夜醒来的最初原因，故排除；B“人们必须半夜回复邮件和Twitter”，文中并没有提到，故排除；D“人们已经养成了半夜醒来的习惯”，文中也没有提到，故排除。

单选题 What does the author mean by saying 'It's a very slippery slope' (Line 1, Para. 2)?

【正确答案】 A

【答案解析】细节归纳题。定位句提到，加州大学旧金山医疗中心睡眠紊乱中心主任David M. Claman博士说，这是条不归路，一旦你拿起手机看时间，你就会查邮件，然后就会因为焦虑睡不着。由此得知，定位句中所提到的“不归路”指的是半夜用手机查看时间所引起的一连串的连锁反应，最后导致睡不着。选项A包含这层意思，故为本题答案。B“查看时间会引起失眠”，与题意不符，故排除；C“手机里的信息会让人们感到沮丧”，文中提到的是焦虑不是沮丧，故排除；D“智能手机会在半夜叫醒人们”，文中没有提到，故排除。

单选题 How does the author think about the integration of the clock and the phone?

【正确答案】 B

【答案解析】细节推断题。第三段第五、六句提到，现在新出现的闹钟大多是跟智能手机绑定在一起的。这和多年来的研究结果是相悖的，研究表明无论什么尺寸的电子设备屏幕都是不利于我们入睡的。由此得知，闹钟与智能手机的结合可能会影响睡眠，故答案为B。A“它很好，因为它方便人们使用”，文中没有提及，故排除；C“它对人们没什么吸引力”，与文章意思不符，故排除；D“它违背了手机制造商的利益”，与文章意思不符，故排除。

单选题 What will happen if you take two hours to use a tablet before sleeping?

【正确答案】 B

【答案解析】细节辨认题。由第四段可知，注视智能手机和平板电脑发出的蓝光会触发让我们保持清醒的大脑受体，从而干扰生物钟，如果一个人在睡前使用平板电脑的时间达到2个小时或更多，他想要入睡就需要再多花1个小时。B与第四段意思相符，故为本题答案。A“这会让你更容易入睡”与文章意思不符，故排除；C“这会让你第二天早晨晚起”和D“这会对你的健康有害”，文中没有提到，故排除。