# Có … mới: only if / to … you have to in Vietnamese (B1)

> To say that one thing happens only if another does, put the condition first and mới before the result: Phải tập mỗi ngày mới nói giỏi được.

Source: https://vietnamesebuddy.com/grammar/co-moi-only-if/ · Updated 2026-10-17

**only if / to … you have to**

Pattern: `(Phải / Có) + [condition] + (person) + mới + [result] · Muốn + [result] + (thì) + phải + [condition]`

Level: B1 (our estimate) · Register: everyday

Typed without accents: co … moi, phai … moi, muon … thi phai

To say that one thing happens only if another does, put the condition first and *mới* before the result: *Phải tập mỗi ngày mới nói giỏi được.* You only get good at speaking by practising every day (literally, must practise every day, only then speak well). *Thì* often comes before *mới*: *phải … thì mới …*.

The same idea can start from the goal: *muốn* (want) and the result, then *thì phải* and what it takes: *Muốn nói giỏi thì phải tập mỗi ngày.* If you want to speak well, you have to practise every day. The two frames say the same thing in opposite order.

*Có … mới* is the version for having or doing something: *Có tiền mới mua được.* You can only buy it if you have the money. If the result has its own person, that person comes just before *mới*: *Phải có hẹn trước thì bác sĩ mới khám.*

This is the same *mới* as in *Mười giờ anh ấy mới tới*, he didn't come until ten: what comes before *mới* has to happen first. *Chỉ khi* (only when) works the same way and also takes *mới*: *Chỉ khi em học thì em mới giỏi.* *Nếu … thì* (if … then) just sets a condition; *phải … mới* says it's the only way.

## A common mistake

✗ Chỉ nếu em học, em sẽ giỏi.

✓ Em phải học thì mới giỏi.

*Chỉ nếu* sounds like a translation. Vietnamese says "only if" with *mới*: *phải … thì mới*, or *chỉ khi … thì mới*.

## Examples

- Phải tập mỗi ngày mới nói giỏi được. — You only get good at speaking by practising every day.
- Muốn nói giỏi thì phải tập mỗi ngày. — If you want to speak well, you have to practise every day.
- Phải đặt bàn trước thì mới có chỗ. — You only get a table if you book ahead.
- Phải có hẹn trước thì bác sĩ mới khám. — The doctor only sees you with an appointment.

## Compare

- [Not until, only then: time + mới](https://vietnamesebuddy.com/grammar/moi-not-until/): only then
- [If … then: nếu … (thì)](https://vietnamesebuddy.com/grammar/neu-thi-if/): if

Previous in Time and when things happen: [Only (so few, so young): mới + number](https://vietnamesebuddy.com/grammar/moi-only-number/)
Next in Time and when things happen: [Suddenly: tự nhiên, tự dưng, bỗng (nhiên)](https://vietnamesebuddy.com/grammar/bong-suddenly/)

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