Do you wake _21__very day feeling too tired,or even upset?If

Do you wake _21__very day feeling too tired,or even upset?If so,then a new alarm clock could be just for you.
The clock,called Sleep smart,measures your sleep cycle,and waits__22_you to be in your lightest phase of sleep__23_rousing you.Its makers say that should_24__you wake up feeling refreshed every morning.
As you sleep you pass__25_a sequence of sleep states—light sleep,deep sleep and REM(rapid eye movement) sleep---that__26_approximately every 90 minutes.The point in that cycle at which you wake can_27__how you feel later,and may_28__have a greater impact than how much or little you have slept.Being roused during a light phase__29_you are more likely to wake up energetic.
SliipSmart_30__the distinct pattern of brain waves _31__during each phase of sleep,via a headband equipped_32__electrodes and a microprocessor.This measures the electrical activity of the wearer’s brain,in much the_33__way as some machines used for medical and research_34__and communicates wirelessly with a clock unit near the bed.You_35__the clock with the latest time at _36__you want to be wakened,and it_37__duly wakes you during the last light sleep phase before that.
The concept was invented by a group of students at Brown University in Rhode Island_38__a friend complained of waking up tired and performing poorly on a test.”_39__sleep---deprived people ourselves,we started thinking of_40__to do about it,” says Eric Smashup,a recent college graduate and now chief executive officer of Axon Sleep Research Laboratories,a company created by the students to develop their idea.
21 A up B at C on D with
22 A beside B near C for D around
23 A upon B before C towards D till
24 A ensure B assure C require D request
25 A through B into C about D on
26 A reveals B reverses C resumes D repeats
27 A effect B affect C reflect D perfect
28A already B ever C never D even
29A means B marks C says D dictates
30A removes B relieves C records D recalls
31A proceeded B produced C pronounced D progressed
32A by B of C with D over
33A fuller B similar C identical D same
34A findings B prospects C proposals D purposes
35A prompt B program C plug D plan
36A where B this C which D that
37A then B also C almost D yet
38A once B after C since D while
39A besides B despite C to D as
40A what B how C whether D when

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