once
/wʌns/ (bre, ipa) · [wˈʌns] /wʌns/ (ame, ipa) · [wˈʌns] /ˈwən(t)s/ (ame, mw)
once — adverb
1. one time only, or one time in each period you name.
one time only, or one time in each period you name.
Maya has driven a tractor only once, on her uncle's farm.
only once for a single occurrence
The twins call their grandmother once a week after Sunday lunch.
once + a week for regular frequency
Carlos checked the door lock once before leaving the apartment.
I saw snow in Tainan once, when I was six.
- one time
a looser paraphrase; less natural than 'once' in most everyday sentences
- a single time
more emphatic when you want to stress the number
- repeatedly
shows that something happens again and again
- often
focuses on high frequency rather than one occurrence
文法句型
once + clause
once + a/an + time unit
用法筆記
With a period noun, it marks one event in each period: once a week, once a night. Without that time phrase, it usually means only one occasion.
常見錯誤
2. at the same moment, with more than one thing happening together.
at the same moment, with more than one thing happening together.
Three phones rang at once during the meeting with the bank.
at once = at the same time
The children all shouted at once when the cake appeared.
Rain and strong wind hit the tents at once after midnight.
Lina cannot answer two customers at once at the busy stall.
- simultaneously
more formal and common in written English
- together
weaker, because it does not always stress the exact same moment
- separately
shows that events or actions happen apart from each other
- one by one
emphasises sequence instead of simultaneity
文法句型
at once
do two things at once
用法筆記
Almost always appears in 'at once'. Distinguish from the idiom 'at once' meaning 'immediately'; here the focus is simultaneity.
常見錯誤
3. on this occasion, unlike what usually happens.
on this occasion, unlike what usually happens.
For once, Marcus arrived early and brought coffee for everyone.
for once = unlike the usual pattern
For once, the printer worked well before the morning class began.
The baby slept through the night for once after the fever.
For once, our team kept the kitchen clean after lunch.
- for a change
more conversational; often expresses relief or surprise
- unusually
more descriptive and less tied to the fixed phrase
- as usual
shows that nothing different happened this time
文法句型
for once + clause
用法筆記
Usually in the fixed phrase 'for once' and often near the start of the clause. Distinguish from sense 4: sense 3 comments on an unusual result, while sense 4 gives permission for a one-time exception.
常見錯誤
4. only on this occasion, as a special exception to the usual rule.
only on this occasion, as a special exception to the usual rule.
I'll lend you my bike just this once, so be careful.
just this once = single exception
The guard let Maya in just this once without her pass.
Mrs. Lin agreed to swap shifts just this once for Carlos.
Dad said we could order pizza just this once after finals.
- this time only
plain paraphrase often used in warnings or instructions
- as a special case
more formal and common in written notices or official speech
- every time
shows that the action is normal, not exceptional
- as a rule
states the usual policy rather than an exception
文法句型
just this once
this once
用法筆記
Usually follows a promise, refusal, or request: 'just this once'. Distinguish from sense 3: this sense allows an exception instead of describing what was unusual.
常見錯誤
5. used when the same situation or problem comes back another time.
used when the same situation or problem comes back another time.
Once again, the train stopped outside Taichung for forty minutes.
once again before the main clause
The old roof leaked once again during last night's storm.
Once again, voters asked the mayor about rising food prices.
The dog barked once again when the postman reached the gate.
- for the first time
marks a new event instead of a repeated one
文法句型
once again + clause
clause + once again
用法筆記
Most often appears as sentence-level 'once again' to comment on a familiar situation returning. Distinguish from sense 6, which asks for one extra performance of an action, and from sense 7, which more often shows a previous state coming back.
常見錯誤
6. one additional time, especially when you want to do or hear something again.
one additional time, especially when you want to do or hear something again.
Please play the last line once more for the choir.
once more after an action verb
Maya knocked once more before opening the classroom door.
The guide asked us to read the map once more.
Can you explain that step once more with a simple example?
- again
neutral and very common, but less explicit about the extra round
- over again
more conversational, especially in American English
文法句型
verb + once more
用法筆記
Most often appears as 'once more' after verbs like say, read, hear, or try. Distinguish from sense 5, which more often introduces a situation returning again.
常見錯誤
7. so that an earlier state, feeling, or condition is there again.
so that an earlier state, feeling, or condition is there again.
After the nurse smiled, Mr. Chen felt calm once more.
once more after a returning feeling
By spring, green leaves covered the old mango tree once more.
When the power returned, the hallway became bright once more.
After two quiet weeks, the harbor was busy once more.
文法句型
clause + once more
become/feel/be + adjective + once more
用法筆記
Usually appears as clause-final 'once more', especially with verbs like be, become, feel, and seem. Distinguish from sense 5: sense 5 comments on the same event happening again, while this sense shows an earlier state returning.
8. one or two times, and not very often.
one or two times, and not very often.
I have met her once or twice at Ken's birthday dinners.
verb + once or twice
The old printer jammed once or twice during the office move.
Marcus has cooked curry once or twice, but never for guests.
A deer crossed the road behind our village once or twice last winter.
- a couple of times
slightly more conversational
- a few times
can suggest more than two
文法句型
verb + once or twice
once or twice, + clause
用法筆記
Mostly used as the fixed phrase 'once or twice' for a rough small number. It sounds less exact than saying 'two times'.
9. sometimes, with fairly long gaps between one time and the next.
sometimes, with fairly long gaps between one time and the next.
We still eat at that noodle shop every once in a while.
every once in a while
Every once in a while, Marcus calls his aunt in Taitung.
sentence-initial every once in a while
The old lift stops between floors once in a while.
I buy fresh lilies from that corner stand every once in a while.
- occasionally
more formal and less phrase-like
- from time to time
similar meaning, slightly more neutral
文法句型
once in a while
every once in a while
用法筆記
Usually appears in the phrases 'once in a while' or 'every once in a while'. It is more everyday in tone than the single-word adverb 'occasionally'.
10. in a final and complete way, so the matter will not need attention again.
in a final and complete way, so the matter will not need attention again.
The judge ended the family fight once and for all.
verb + once and for all
Nina cleaned the garage once and for all before winter came.
Let's settle the club rules once and for all tonight.
A new lock fixed the gate problem once and for all.
文法句型
verb + once and for all
用法筆記
Almost always used as the fixed phrase 'once and for all'. It commonly follows verbs like settle, end, fix, decide, or answer.
常見錯誤
11. describing something that most people can expect only one time in their life.
describing something that most people can expect only one time in their life.
Seeing snow on Yushan was a once-in-a-lifetime moment for Lina.
once-in-a-lifetime + noun
For Marcus, singing at the palace felt like a once-in-a-lifetime chance.
The family saved money for years for this once-in-a-lifetime trip.
Meeting the film star backstage was a once-in-a-lifetime surprise.
- rare
much broader and less emotional
- unrepeatable
stresses that it cannot happen again
文法句型
once in a lifetime
once-in-a-lifetime + noun
用法筆記
Usually appears in the phrase 'once in a lifetime', often before nouns like chance, trip, experience, or opportunity.
12. at one particular time, often before you tell the story of what happened.
at one particular time, often before you tell the story of what happened.
Once, my father locked himself out in his slippers.
Once, + clause in storytelling
Once, we found a tiny owl inside the school gym.
Once, Dr. Tanaka treated a singer before a live TV show.
Once, a strong wind blew our picnic blanket into the lake.
- one day
storytelling phrase with a looser sense of time
- on one occasion
more formal and explicit
文法句型
Once, + clause
用法筆記
Often comes at the start of a sentence in stories or memories. Distinguish from sense 1, which counts how many times something happened rather than introducing one remembered event.
13. formerly; during an earlier period, for a role, condition, or place that later c
formerly; during an earlier period, for a role, condition, or place that later changed.
This village was once a quiet fishing town on the east coast.
was once + noun phrase for former identity
Marcus once worked in his aunt's small bakery near the station.
once + past verb for former job
The old cinema was once the busiest place in the town square.
Many families here once kept chickens behind their houses.
Taipei 101 was once the tallest building in the world.
- formerly
closest single-word match, especially in writing
- previously
often used for earlier jobs, steps, or situations
- in the old days
more conversational and broader in time
文法句型
once + past verb
be + once + noun/adjective
用法筆記
Often comes before the main verb or after 'be': 'once worked here', 'was once famous'. Distinguish from senses 1 and 12, which count a single occasion rather than describe a former state.
常見錯誤
once — conjunction
1. after a stated event happens, or beginning from that point in time.
after a stated event happens, or beginning from that point in time.
Once Maya signs the lease, she can move in on Friday.
once + present clause for future result
Once the snow melts, this road stays open until October.
starting point for a continuing state
Once Grandpa retired, he spent every morning at the riverside park.
Once the baby falls asleep, the whole apartment becomes quiet.
Once our names were on the list, we could enter freely.
- when
broader and less focused on the starting point of the new situation
- after
shows sequence, but does not stress the new state beginning at that moment
- from the time
more formal and usually emphasizes what continues afterward
文法句型
once + present simple clause, main clause
once + past event clause, continuing result
用法筆記
Often marks the start of a new situation that continues after that moment. Distinguish from sense 2, which focuses more on the next action happening straight away.
常見錯誤
2. at the exact moment that something happens, with no delay before the next event.
at the exact moment that something happens, with no delay before the next event.
Once Leo heard the fire alarm, he ran downstairs.
immediate action after once-clause
Once the light turned green, the first taxi moved.
Once the nurse called my number, I walked straight in.
Once Tina saw the empty shelf, she phoned the supplier.
Once the bell rang, the children rushed into the yard.
- as soon as
the closest everyday equivalent for immediate sequence
- the moment
more vivid and often slightly more dramatic
- when
less specific because it does not always imply no delay
文法句型
once + event clause, immediate action
用法筆記
Common when one event triggers the next one immediately. Distinguish from sense 1 when you want to stress a longer state that begins after the first event.