Grammar 70: “Expressions indicating the speed/passage of time

Vietnamese has a wide variety of expressions to describe how quickly time passes. By learning to use them appropriately depending on the context—from daily conversation to literary expressions—you will be able to speak Vietnamese more naturally and fluently.
In this lesson, we will introduce expressions for the speed of time, divided into three groups.

① In the blink of an eye (Metaphorical and Literary Expressions)

These expressions describe time passing in an instant, often using imagery such as the eyes or blinking.

Expression	Meaning / Example Sentence
Chớp mắt một cái	(In the blink of an eye) In an instant. Very common, used to emphasize how quickly something happened.
Thấm thoát	(Before you know it) Used when looking back on a long period, such as months or years, that has passed by quietly.
Vèo một cái	(In a flash / Whoosh) A casual expression. Used for short periods, like a vacation or an afternoon, that seem to fly by.
Trong nháy mắt	(In a split second / In the blink of an eye) Similar to “chớp mắt,” it emphasizes something happening instantly.
Vụt một cái	(Suddenly / In a dart) Expresses a change or movement happening at a surprising speed.

① Chớp mắt một cái, con trai tôi đã trưởng thành rồi.
→ In the blink of an eye, my son has grown up.

② Thấm thoát đã 3 năm kể từ khi tôi đến Việt Nam.
→ Before I knew it, 3 years have passed since I came to Vietnam.

③ Kỳ nghỉ hè trôi qua vèo một cái.
→ Summer vacation flew by in a flash.

④ Anh ấy đã giải xong bài toán khó đó trong nháy mắt.
→ He solved that difficult math problem in a split second.

⑤ Con mèo vụt một cái đã nhảy lên mái nhà.
→ The cat darted onto the roof in a flash.

② Continuity of actions (Expressions for Conversation and Narration)

Expression	Meaning / Example Sentence
Chưa kịp… đã…	(Before even having time to…, … already happened). Expresses surprise or a sense of being rushed when a new situation occurs before the previous action is completed.
Ngoảnh đi ngoảnh lại	(Before you know it / In the blink of an eye). Expresses the feeling of a significant amount of time passing while you were slightly distracted or focused on something else.
Mới đây mà…	(It feels like just yesterday…). Expresses a sense of disbelief when something you thought happened very recently is actually already far in the past.
Loáng một cái	(In a flash / In an instant). Refers to an action being completed extremely quickly or a short amount of time passing all at once.

① Chưa kịp ăn xong bát cơm đã hết giờ nghỉ.
→ Before I even finished my bowl of rice, my break was already over.

② Ngoảnh đi ngoảnh lại, trời đã tối rồi.
→ Before I knew it (when I looked back), it was already dark outside.

③ Mới đây mà đã đến Tết rồi.
→ It feels like just yesterday, but Tet (Lunar New Year) is already here.

④ Loáng một cái, anh ấy đã làm xong hết việc.
→ In a flash, he finished all of his work.

③ Formal Expressions and Expressions Showing Strong Emotion

These are highly formal expressions used in writing, or phrases that emphasize the speed of a specific subject.

Expression	Meaning / Example Sentence
Chẳng mấy chốc	“Before long” or “soon.” Used to predict that a future event is coming quickly. Chẳng mấy chốc chúng ta sẽ gặp lại nhau.
Nhanh như thổi	“Growing like a weed” (literally: fast as the blowing wind). Primarily used when a child grows remarkably fast. Đứa bé lớn nhanh như thổi.

① Nếu cứ đà này, chẳng mấy chốc chúng ta sẽ đến nơi.
→ At this rate, we will arrive at our destination before long.

② Thằng bé lớn nhanh như thổi.
→ The boy grew up fast like a weed.