`Asleep` is not really the word `sleep` — it is `a-` + `sleep`, an old way of saying "in sleep", the way `ashore` means "on the shore". So it names a place someone is currently in rather than a thing they do. That is why it lives after the verb (`the baby is asleep`, `he fell asleep`) and not in front of a noun. And once sleep is a place, other things can be in it too: a leg, a person's attention, even a life that has ended.
From the word’s history
From Old English on slæpe, "in sleep" — the a- here is the old preposition an/on "on, in", the same a- that makes ashore, afloat, alive. Middle English aslepe is recorded around 1200, and the parallel form on sleep survived until about 1550. The numb-limb sense is already there in the late 1300s.
asleep 來自古英語 on slæpe，字面就是「在睡眠裡」；開頭的 a- 是古老的介系詞 an/on（在…之上、在…之中），跟 ashore、afloat、alive 的 a- 是同一個。中古英語 aslepe 約在 1200 年出現，而寫成兩個字的 on sleep 一直用到 1550 年左右。手腳發麻的那個意思，1300 年代末就已經有了。
Online Etymology Dictionary, entry "asleep" (etymonline.com/word/asleep)
登入就可以看每一支怎麼連回核心畫面。
原始詞典資料4 筆記錄
以下是外部詞典記錄的用法，摘錄並精簡格式，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
asleepadj/əˈsliːp/
- 1
In a state of sleep; also, broadly, resting.
- I was asleep when you called.
- Never disturb a man asleep.
- 2
slangInattentive.
- How could you miss that? Were you asleep?
- The reason they call it the American Dream is because you have to be asleep to believe it.
- 3
Having a numb or prickling sensation accompanied by a degree of unresponsiveness.
- My arm fell asleep. You know, like pins and needles.
- Louisa sat in the car crying, until her foot fell asleep. She shook her foot violently, afraid the numbness would turn to frostbite.
- 4
Dead.
摘錄自 英文維基詞典 English Wiktionary，已精簡格式；依 CC BY-SA 4.0 授權使用，改動後的內容同樣以此授權提供。