Ⅰ.语法填空
Should naps(小睡) actually __1__ (take) during the day? Well, we certainly know from __2__ (evident) in the sleep center and that of many other scientists that naps can give you benefits for both your brain __3__ your body. But naps can actually be __4__ doubleedged sword because while we're awake during the day, we're building up sleepiness or sleep pressure. So when you try to fall asleep at night, you'll fall asleep quickly and then you'll stay asleep. And when we sleep, we actually release that sleepiness so that we wake up the next morning feeling __5__ (refresh).
So if you take a nap during the day, especially if you take it too late in the afternoon, you will actually release some of that sleepiness and it will make it much __6__ (hard) to fall asleep and stay asleep soundly throughout the night. So the advice would be if you don't struggle with your sleep and you can nap __7__ (regular), then naps are just fine.
But if you do find it difficult __8__ (fall) asleep or stay asleep at night, then you should avoid naps and try to build up that healthy sleepiness in the evening.
The ideal nap depends on __9__ you want from that nap. Different stages of sleep actually give you different types of brain and body __10__ (benefit)．
