通常当我们累了/困了，我们会说：I am going to sleep.但是这一种说法太无聊了，中文还有小憩、就寝、打盹、入眠等说法呢。
- Take a nap
A nap is basically a very short of sleep
例句：I am sure if i take a quick nap,i will feel really fresh.
- Call it a night
This is basically a phrase you would use when say you're done for the day.You've done whatever you had to do and you really just need to go off to sleep.
To finish every work and go off to sleep
例句：Well the party is amazing but i am really tired now and i think i need to call it a night.
- Hit the sack
When you are extremely sleepy and you need to go to sleep like almost instantly.
例句：Well i have worked really long hours today and i'm going to hit the sack as soon as i reach home.
- Get some shut eye
To sleep for a short period.很随意的表达方式
例句：I've been studying for hours and i really need to get some shut eye.
- Snooze for a while
To sleep for some time(just a short period of time)
例句：I am really tired driving so why don't you take over the wheel and i will just snooze for a while ,so i'll feel fresh.
- Doze off
To just sleep immediately.打瞌睡
例句：The lecture in college was so boring today that i just dozed off.I didn't know what happened post that.
- Take a siesta
Sleeping for some time after your noon meal
例句：I love taking a siesta once in a while,it just helps me to feel much more fresher and active later on.
好了，介绍完了，如果你还知道‘I need some sleep'的其他表达方式，欢迎留言分享。也欢迎在评论里留下例句的翻译，方便一些英语不是很好的小伙伴理解。