Do you wake up every day feeling too tired, or even upset? If so, then a new alarm clock could be just for you.

The clock, called SleepSmart, measures your sleep cycle, and waits【C1】_____you to be in your lightest phase of sleep【C2】__rousing you. Its makers say that should【C3】_____you wake up feeling refreshed every morning.

As you sleep you pass【C4】_____a sequence of sleep states—light sleep, deep sleep and REM (rapid eye movement) sleep—that【C5】__approximately every 90 minutes. The point in that cycle at which you wake can 【C6】__how you feel later, and may【C7】__have a greater impact than how much or little you have slept. Being roused during a light phase【C8】_____ you are more likely to wake up energetic.

SleepSmart【C9】_____the distinct pattern of brain waves【C10】__during each phase of sleep, via a headband equipped【C11】__electrodes and a microprocessor. This measures the electrical activity of the wearer’s brain, in much the 【C12】__way as some machines used for medical and research【C13】__, and communicates wirelessly with a clock unit near the bed. You【C14】__the clock with the latest time at which you want to be【C15】__, and it【C16】_____ duly wakes you during the last light sleep phase before that.

The【C17】_____was invented by a group of students at Brown University in Rhode Island【C18】__a friend complained of waking up tired and performing poorly on a test. “【C19】__sleep-deprived people ourselves, we started thinking of【C20】_____to do about it,” says Eric Shashoua, a recent college graduate and now chief executive officer of Axon Sleep Research Laboratories, a company created by the students to develop their idea.

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