# Khi / khi … thì: when (+ sentence) in Vietnamese (A2)

> Khi means "when" and joins two sentences: Khi rảnh, tôi hay đi bơi. When I'm free, I often go swimming.

Source: https://vietnamesebuddy.com/grammar/khi-when/ · Updated 2026-10-17

**when (+ sentence)**

Pattern: `Khi + [sentence] (thì) + [sentence]`

Level: A2 (our estimate) · Register: everyday

Typed without accents: khi, khi … thi

Variants:

- lúc + [sentence] (speech)

*Khi* means "when" and joins two sentences: *Khi rảnh, tôi hay đi bơi.* When I'm free, I often go swimming. The *khi* part usually comes first, then what happens.

When the *khi* part comes first, the second part often opens with *thì*, a small "then": *Khi em tới thì chị Lan về rồi.* When I got there, Lan had already gone home. *Thì* is common in speech and can be left out. If the *khi* part comes second, there's no *thì*: *Tôi không thích ra đường khi trời mưa.*

In Saigon conversation, *lúc*, which you know from clock times, often takes the place of *khi*: *Lúc mới qua Việt Nam, tôi không biết nói gì hết.* *Khi* is the usual word in writing.

The verb stays the same for past, present and future; the rest of the sentence shows when, with words like *rồi*, *sẽ* or a time word.

*Khi* on its own doesn't ask anything. To ask "when?", use *khi nào* or *bao giờ*: *Khi nào em về?* For two things going on at once, "while", use *trong khi*.

## Examples

- Khi rảnh, tôi hay đi bơi. — When I'm free, I often go swimming.
- Saigon: Khi em tới thì chị Lan về rồi. | Hà Nội: Khi em đến thì chị Lan về rồi. — When I got there, Lan had already gone home.
- Tôi không thích ra đường khi trời mưa. — I don't like going out when it rains.
- Saigon: Lúc mới qua Việt Nam, tôi không biết nói gì hết. | Hà Nội: Lúc mới sang Việt Nam, tôi không biết nói gì cả. — When I first came to Vietnam, I couldn't say anything at all.

## Words in this pattern

- [khi](https://vietnamesebuddy.com/words/khi-when/#s_khi_when): when

## Compare

- [At a time: lúc / vào lúc, vào + day](https://vietnamesebuddy.com/grammar/vao-luc-at-time/): at / on (time)
- [While: trong khi, and khi … đang for an interrupted action](https://vietnamesebuddy.com/grammar/trong-khi-while/): while
- [When? bao giờ / khi nào: first for the future, last for the past](https://vietnamesebuddy.com/grammar/bao-gio-when/): when?
- [Before and after doing: trước khi / sau khi](https://vietnamesebuddy.com/grammar/truoc-khi-sau-khi/): before / after (+ action)
- [If … then: nếu … (thì)](https://vietnamesebuddy.com/grammar/neu-thi-if/): if
- [Hearing this, seeing that: a verb phrase before the subject (Nghe tin, cô ấy khóc)](https://vietnamesebuddy.com/grammar/fronted-verb-phrase/): on hearing / seeing …, the subject …
- [Back when: hồi + time (hồi nhỏ, hồi đó)](https://vietnamesebuddy.com/grammar/hoi-back-when/): back when, at the time of

Previous in Time and when things happen: [Since: từ … (tới giờ), từ khi, từ khi nào](https://vietnamesebuddy.com/grammar/tu-since/)
Next in Time and when things happen: [While: trong khi, and khi … đang for an interrupted action](https://vietnamesebuddy.com/grammar/trong-khi-while/)

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