Phrase
at once
adverb
立刻；马上
immediately; without delay
- 1.
At the same time; simultaneously; together.
同时；一起
- 2.
Immediately; now; right away.
立即；马上；立刻
同时；一起；立即；马上；立刻；立刻
In use
When the fire alarm rang, we left the building at once.
Please call me at once if you hear any news.
She recognized the mistake and corrected it at once.
verb + at once (imperative)
祈使句中常用。
Go at once.
立刻去。
subject + must + verb + at once
You must answer at once.
你必须立刻回答。
subject + verb (past) + at once
也可用于过去时。
He left at once.
他立刻离开了。
Common mistakes
I have been to Beijing at once.I have been to Beijing once.
“at once”表示“立刻”，不表示“一次”。表示“一次”应用“once”。
At once I finish, I will call you.As soon as I finish, I will call you.
“at once”是副词短语，不能用作连词引导时间状语从句。表示“一…就…”应用连词“as soon as”。
Connections
Confusing words
- once
- 一次；一旦 · once 表示“一次”或“一旦”，与 at once（立刻）因形式相似易混淆，但意义不同。
- immediately
- 立即 · immediately 与 at once 在“立刻”意义上基本同义，但 immediately 更正式，而 at once 更口语化。
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY.