Do you know the reason why we feel tired in the middle of a class？Maybe you would say it is because the teacher's class is boring.（1）

B

B

Perhaps this is something you have not paid enough attention to or not yet noticed.
   Purpose of sleep
   Why do we need sleep？Sleep helps our body heal（修復(fù)）grow and stay healthy.It also gives us energy，so we can be active all day.Doctors and health scientists say：when you close your eyes and need to rest，sleep is just the very best!
   Sleep time
   Enough sleep is important to us.How much sleep do we need？New-born babies can sleep 20—22 hours a day.Teenagers need 8—10 hours of sleep a day because they need lots of energy to grow into their adult bodies.Grown-ups usually need 6—8 hours of sleep to keep active.（2）

D

D

That is why old people sleep less than young people.
   Interesting facts
   Almost everyone has their dreams while they sleep，but not all of them can tell their dreams clearly when they wake up.Some people talk in their dreams.（3）

A

A

This is called "sleepwalking".Are you a sleepwalker？Or is there a sleepwalker around you？
   Sleepy animals
   It's not just people that love to snooze（打盹）.（4）

C

C

Some animals，such as bears and hedgehogs（刺猬），sleep all through winter.The swift（雨燕）is a very fast bird that can sleep while it flies!Cute koalas sleep around 18 hours a day.Giraffes don't need much sleep at all.They usually sleep standing up.

根據(jù)短文內(nèi)容，從下列選項(xiàng)中選出能填入文中空白處的最佳選項(xiàng)，其中有一項(xiàng)為多余選項(xiàng)。
A．More surprisingly，some may even get up in their dreams and walk around.
B．However，the real reason is probably that we don't have enough sleep.
C．In fact，many animals have unusual or surprising sleeping habits.
D．The older you get，the less sleep you will need.
E．Many animals also need as much sleep as people.