lúc

At (A Clock Time)

Level 2

Lúc means 'at' and is used to pinpoint an exact clock time or specific moment.

How It Works

In Vietnamese, lúc is the standard, everyday word used to express 'at' a specific clock time. Fundamentally, it functions as a noun meaning 'moment' or 'time'.

1. With Clock Times
Place lúc directly before the time: lúc 6 giờ (at 6 o'clock). For a more complete or formal expression, you can combine it with vào to make vào lúc 6 giờ.

2. The Difference Between Lúc, Khi, and Vào
Learners often confuse words for 'when' and 'at'. Here is the rule:

  • Lúc is the standard word for exact clock times, though it is frequently omitted in casual speech (e.g., Tôi thức dậy 6 giờ sáng). It can also introduce clauses (e.g., lúc tôi đến - when I arrived).
  • khi is used for broader timeframes or introducing clauses. It is often interchangeable with lúc for clauses, but you cannot use khi as the preposition 'at' for clock times (do not say khi 6 giờ to mean 'at 6 o'clock', though the phrase can appear in structures like đến khi 6 giờ - until 6 o'clock).
  • vào is for larger calendar units like days, months, and years (e.g., 'on Monday'), but it can also be used directly before a clock time without lúc (e.g., Tôi có hẹn vào 6 giờ tối nay).

3. Sentence Position
A time phrase using lúc is highly flexible. It naturally belongs at the beginning or the end of a sentence (e.g., Lúc 6 giờ tôi đang ngủ or Tôi đang ngủ lúc 6 giờ). (See time phrase position).

4. Asking Questions
To ask 'at what time' or 'when', use lúc mấy giờ (for specific clock times) or lúc nào (for general times). For lúc nào, its position in the sentence sets the tense if markers like đã or sẽ are omitted: placing it at the beginning asks about the future, while placing it at the end asks about the past. However, lúc mấy giờ is more flexible and can often appear at either end regardless of tense. Note that in casual spoken Vietnamese, lúc is frequently omitted in questions (e.g., Mấy giờ anh đi? instead of Lúc mấy giờ anh đi?).

5. Common Time Phrases and Patterns
Because lúc is a noun, it pairs naturally with demonstratives to create everyday vocabulary: lúc này (at this moment / now) and lúc đó or lúc ấy (at that moment / then). Another highly frequent core word is lúc nãy (a moment ago / just now). You can also use lúc with parts of the day (e.g., lúc sáng nay - this morning, lúc nửa đêm - at midnight). Other essential phrases include trong lúc (while / in the moment), có lúc (sometimes), đúng lúc (just in time), lúc nào cũng (always), and bất cứ lúc nào (anytime). You will also see the pattern lúc..., lúc... to mean 'sometimes A, sometimes B' (e.g., lúc nắng, lúc mưa - sometimes sunny, sometimes rainy).

Examples (4)

  1. Tôi dậy lúc sáu giờ.

    I get up at six o'clock.

    Word by Word: I wake-up moment six hour.

    The most common everyday use of 'lúc' is directly before a clock time.

  2. Tuần sau, chúng ta sẽ họp lúc 9 giờ sáng.

    Next week, we will have a meeting at 9 AM.

    Word by Word: Week after, we will meet moment 9 hour morning.

    Notice how the time phrase 'lúc 9 giờ sáng' is placed at the very end of the clause.

  3. Tên trộm đột nhập vào nhà lúc 6 giờ tối.

    The burglar broke into the house at 6 PM.

    Word by Word: Name thief break-in enter house moment 6 hour evening.

    Used to pinpoint the exact moment an event occurred in the past.

  4. Lúc đó, tôi đang ngủ.

    At that moment, I was sleeping.

    Word by Word: Moment that, I in-progress sleep.

    'Lúc' can also attach to demonstratives like 'đó' (that) to refer to a specific instant in time.

Common Mistakes

  • Using 'khi' instead of 'lúc' for clock times.

    Tôi ăn sáng khi 7 giờ.
    Tôi ăn sáng lúc 7 giờ.

    While both 'lúc' and 'khi' can introduce clauses meaning 'when', 'khi' cannot be used before a specific clock time. You must use 'lúc' (or 'vào lúc').

  • Using 'lúc' for days of the week or months.

    Tôi sẽ đi lúc thứ Hai.
    Tôi sẽ đi vào thứ Hai.

    'Lúc' is strictly for clock times and specific moments. For larger calendar units like days, months, or years, you must use 'vào'.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

lúcLevel 2At (A Clock Time)

Learn This First

To use 'lúc' for clock times, you need a basic grasp of Vietnamese word order to place the time expression correctly (usually at the end or beginning of the sentence). You also need to be familiar with numbers and the question word 'mấy' to ask or state specific hours.

Words in This Pattern

lúc