In Vietnamese, we use khi nào to ask “when”. Compared to other question words, khi nào is quite special in that its position in the sentence greatly affects the meaning of the sentence.
Structure
Place khi nào at the start of the sentence to ask “when” in the future.
Khi nào + …?
Alternatively, place khi nào after the subject.
subj. + khi nào + …?
Place khi nào at the end of the sentence to ask “when” in the past.
… + khi nào?
However, if there is a preposition in combination with “when”, such as đến (“until”), always place khi nào at the end no matter if it’s the future or the past.
Two alternatives to khi nào are bao giờ and lúc nào (same meaning).
Examples
- Khi nào anh bắt đầu?
When will you start? - Anh ấy biết từ khi nào?
Since when did he know? - Họ ở Việt Nam tới khi nào?
Until when are they going to stay in Vietnam? - Anh học tiếng Việt từ lúc nào?
Since when have you been learning Vietnamese? - Bao giờ bố về?
When will dad be back?
Usage notes
In Vietnamese, there are three different time phrases with giờ:
| Vietnamese | English |
|---|---|
| bao giờ | when |
| bao nhiêu giờ | how many hours |
| mấy giờ | what time |
Be careful not to mix them up.