once

1. ADV If something happens once, it happens one time only. 一次[ADV with v]

I met Miquela once, briefly. 我見過蜜凱拉一次，時間很短。

Since that evening I haven't once slept through the night. 自那晚之後，我再也沒睡過一次囫圇覺。

2. PRON Once is also a pronoun. 一次['the/this' PRON]

"Have they been to visit you yet?"—"Just the once, yeah."

“他們已經去看過你了嗎？”— “來過，就那一次。”

3. ADV You use once with "a" and words like "day," "week," and "month" to indicate that something happens regularly, one time in each day, week, or month. 每隔…一次[ADV 'a' n]

Lung cells die and are replaced about once a week. 肺細胞約每周死亡、更新一次。

4. ADV If something was once true, it was true at some time in the past, but is no longer true. 從前

Her parents once ran a shop. 她父母從前開過一家商店。

I lived there once myself, before I got married. 我從前自己住在那兒，沒結婚前。

5. ADV If someone once did something, they did it at some time in the past. 曾經[ADV with v]

I once went camping at Lake Michigan with a friend. 我曾和一個朋友去密執安湖野營。

We once walked across the frozen pond at two in the morning. 我們曾在淩晨2點徒步橫穿冰凍的池塘。

6. CONJ If something happens once another thing has happened, it happens immediately afterward. 一…就

The decision had taken about 10 seconds once he'd read a market research study. 他讀完一份市場調研報告後，10秒鍾就做出了決定。

7. PHRASE If something happens all at once, it happens suddenly, often when you are not expecting it to happen. 突然

All at once there was someone knocking on the door. 突然有人敲門。

8. PHRASE If you do something at once, you do it immediately. 立刻

I have to go at once. 我得馬上走。

Remove from the heat, add the parsley, toss and serve at once. 從火上耑下來，加入香芹，攪拌後立刻上桌。

9. PHRASE If a number of different things happen at once or all at once, they all happen at the same time. 同時

You can't be doing two things at once. 你不能同時做兩件事。

10. PHRASE For once is used to emphasize that something happens on this particular occasion, that it has never happened before, and may never happen again. 就此一次[強調]

For once, Dad is not complaining. 就這一次，爸爸沒有抱怨。

11. PHRASE If something happens once again or once more, it happens again. 再一次

Amy picked up the hairbrush and brushed her hair once more. 艾米拿起梳子，又梳了一遍頭發。

12. PHRASE If something happens once and for all, it happens completely or finally. 最終地[強調]

We have to resolve this matter once and for all. 我們必須徹底解決這件事情。

13. PHRASE If something happens once in a while, it happens sometimes, but not very often. 偶爾

Your body, like any other machine, needs a full service once in a while. 你的身躰就像其他機器一樣，偶爾也需要一次全麪保養。

14. PHRASE If you have done something once or twice, you have done it a few times, but not very often. 一兩次; 幾次

I visited once or twice. 我蓡觀過一兩次。

Once or twice she had caught a flash of interest in William's eyes. 有一兩次，她捕捉到威廉眼中一閃的關注。