你知道吗？每年的3月21日，是世界睡眠日。
一个人一生有35年都在睡觉，睡眠占了很大的比重。拥有良好的睡眠，真的很重要。看看伟大的莎士比亚是怎么说的：
"Enjoy the honey-heavy dew of slumber."
"O sleep, O gentle sleep, nature's soft nurse, how have I frighted thee?"
下面我们一起来了解睡眠，早日和失眠君说分手！
曾经，人们把睡眠视作对时间的浪费：
At the beginning of the 20th century：
Thomas Edison said: "Sleep is a criminal waste of time and a heritage from our cave days.
用一位神经学家的话来说，我们过去忽视睡眠，甚至错误地把它当成一种疾病：
We've treated sleep as an illness, almost. We've treated it as an enemy. At most now, I suppose, we tolerate the need for sleep, and at worst perhaps many of us think of sleep as an illness that needs some sort of a cure.
为什么会有这样的想法呢？↓
Well, it's because you don't do anything much while you're asleep, it seems. You don't eat. You don't drink. And you don't have sex. Well, most of us anyway. And so, therefore it's -- Sorry. It's a complete waste of time, right?
No!
睡眠是必需品，充足高效的睡眠对我们大有好处；相反地，长期睡眠不足会引发各种不良后果。
生理上：Poor sleep is linked to diseases like
Alzheimer's, cardiovascular disease, stroke and diabetes.
心理上：Sleep also has impact on our mental states. Poor sleep makes us make risky, rash decisions and is a drain on our capacity for empathy.
人际上：When sleep deprivation literally makes us more sensitive to our own pain, it's not so surprising that we have a hard time relating to others and just generally being a good and healthy person when we're sleep-deprived.
1.学习后：to hit the save button on those new memories so that you don't forget.
2.学习前：to actually prepare your brain, almost like a dry sponge（干海绵） ready to initially soak up（吸收；浸泡） new information.睡眠还对我们的记忆能力有很大影响！
Without sleep, the memory circuits of the brain essentially become waterlogged （too wet to absorb any more water）, as it were, and you can't absorb new memories.
深度睡眠时释放的脑电波（brainwaves）和清醒时不同。大脑会释放不同的波，其中，有一种叫δ（delta）波。当这种波处于主导地位的时候，就意味着人进入了“深度睡眠”。
In light sleep and REM（rapid eyes movement）快速眼动, our brain waves are very similar to our brain waves in waking life. But our brain waves in deep sleep have these long-burst brain waves that are very different from our waking life brain waves. These long-burst brain waves are called delta waves.
出于各种原因，很多人翻来覆去睡不着、白天昏昏欲睡想打盹。要扭转这种现象，该怎么做呢？看看这个Tips:
You should get out of bed and go to a different room and do something different.
Only return to bed when you are sleepy, and that way you will relearn the association that you once had, which is your bed is the place of sleep.
So the analogy（类比） would be, you'd never sit at the dinner table, waiting to get hungry, so why would you lie in bed, waiting to get sleepy?
今天，既然标题上写了双语，就再整理一些睡眠相关的英语词汇用法吧，（有一部分在上面的段落中已经出现啦）：
1.表示“睡眠差，休息的不好”的表达
toss and turn 辗转反侧
do not sleep a wink 一夜没合眼
sleeplessness（短期）失眠
sleep depreviation 睡眠不足、缺觉
sleep somnipathy/disorder 睡眠障碍
insomina （长期）失眠，（尤指病理性的）；insomniac 失眠的人，失眠者
（从上到下，似乎睡眠越来越糟糕了呢o(╥﹏╥)o）
大海雀造句（一个悲伤的故事）：
On Tom's birthday, his girlfriend told him “You deserve a better woman”. Sadly, Tom tossed and turned all night. He even did not sleep a wink!
The next day, the drowsy man saw his ex-girlfriend and another guy making sheep's eyes at each other from across the table. Desperatley, he became a poor insomniac and was finally diagonsed with somnipathy.
2.表示“睡眠好”的表达
wake up naturally 自然醒
sleep like a log log:一段木材 睡得好极了，像块木头一样一动不动
sleep like a rock
go off into a deep sleep
sleep well
a heavy sleeper
睡得好的这里就不造句啦，大家自己脑补一下吧。
祝大家都能sleep like a rock，每天wake up naturally！