2．
Do you remember your dreams？Do people have the same dreams？Why do I dream？
There are many questions about dreams．We dream during the REM （快速眼動） stage of sleep．We have about five periods of REM sleep during the night．The first REM cycle （周期） lasts about 10 minutes．As the night goes on，the REM cycle gets longer．By early morning，the REM cycle can last up to 90minutes．Usually，it is in this last REM cycle that we remember our dreams．
Dreams change as people age．People may have several dreams each night．Some are like films and usually in color．They come to us over and over again．That may be because the dreamer is worrying about something and trying to find the answer．Sometimes we wake up with a good feeling from a dream．But often we can't remember the dreams clearly．
It is reported that too much dreaming is bad for our health．The more we sleep，the longer we dream．The mind is hard at work．That is why we may have a long sleep and still feel tired when we wake up．
Do you feel a little sleepy after lunch？Well，that's normal．Your body naturally slows down then．What should you do about it？Don't drink coffee，take a nap，instead．There are many advantages of a daily nap．First of all，you can remember things better and make fewer mistakes．Also，you can learn things more easily after taking a nap．A 20-minute nap can reduce your pressure．Finally，a nap can make you cheerful．
But，there are some simple rules you should follow about taking a nap．First，take a nap at noon，about eight hours after you wake up．In general，a 20-minute nap is the best．If you sleep longer，you may fall into a deep sleep．After waking up，you will feel worse．Also，you should set an alarm clock．That way，you can fully relax during the nap．You don't have to keep looking at the clock so that you don't oversleep．Now，next time you feel sleepy after lunch，don't get stressed．Put your head down，close your eyes and take a nap．
81．According to the article，which of the following is true？C
A．People always ask questions in their dreams．
B．People never dream in their last REM cycle．
C．The first REM cycle is the shortest of the five．
D．It's impossible for people to remember their dreams．
82．According to the article，why do people sometimes have the same dream again and again？A
A．Because they are worried about something．
B．Because they often watch interesting color films．
C．Because they want to remember the dream clearly．
D．Because other people ask them too many questions．
83．The underlined word"nap"in Paragraph 5most probably means"C"．
A．A long walk
B．a(chǎn) kind of drink
C．a(chǎn) short sleep
D．a(chǎn) deep sleep
84．According to the article，which of the following is not an advantage of a daily nap？
A．We can run much faster．
B．We can learn things more easily．
C．We can become happier．
D．We can remember things better．
85．According to the article，which of the following is true？A
A．Dreaming is harmful to our health．
B．The longer we dream，the better we sleep．
C．We should fall into a deep sleep after lunch．
D．We'll feel better after a 20-minute nap at noon．
