C．exchanged

　　D．managed

　　18．A.often

　　B．never

　　C．even

　　D．once

　　19．A.apologies

　　B．promises

　　C．smiles

　　D．words

　　20．A.experience

　　B．honor

　　C．power

　　D．desire

　　三、阅读理解

　　Few of us make money by losing sleep.But three graduate students at Brown University in Providence built a company around sleep deprivation(睡眠不足)．

　　Jason Donahue，Ben Rubin and Eric Shashoua were working late nights in Brown's business and engineering schools—and began thinking about ways to sleep better.They discovered they weren't alone in burning the midnight oil.Around 20% of Americans get less than six hours of rest a night.

　　The friends imagined a smart alarm clock that could track how much time we spend in the most restorative(促使康复的)stages of the sleep cycle：REM(快速眼动)and deep sleep.What would it cost to design such a thing？Five years of research,20 employees，$14 million in funding and a lot of doubting from investors and scientists.

　　The company，Zeo，based in Newton，Mass.，launched its product in June.The Zeo device uses a headband with tiny sensors(传感器)that scan your brain for signs of four sleep states：REM，light，deep and waking sleep.The smart alarm clock displays a graph of your sleep pattern and wakes you as you're transitioning out of REM sleep(which is when you're least sleepy)．In the morning you can upload the data to the company's website，and so track your sleep over time.The cost，$399，includes six months' access to one of Zeo's online sleep coaches.Most of the feedback(反馈)comes in the form of Zeo's ZQ score showing how well you've slept.

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