Hãy dập lửa trước khi đi.

Hãy marks the sentence as an instruction, encouragement, or polite command. In English, it is often similar to please, do, or an instructional imperative.

In this sentence, hãy dập lửa means something like put out the fire as an instruction.

A useful note: hãy is correct here, but it can sound a bit formal, careful, or written. In casual speech, Vietnamese often leaves it out.

Vietnamese often leaves out the subject when it is obvious from context, especially in commands.

So Hãy dập lửa trước khi đi naturally means:

• You, put out the fire before leaving
• but Vietnamese does not need to say you

If needed, a pronoun could be added:

• Anh hãy dập lửa trước khi đi.
• Em hãy dập lửa trước khi đi.

The choice of pronoun depends on who is being addressed.

Dập lửa is a common verb + object combination meaning to extinguish a fire or put out a fire.

• dập = to stamp out, beat down, smother, suppress
• lửa = fire

With lửa, dập specifically means put out/extinguish.

This is a natural collocation in Vietnamese. Learners should remember it as a set phrase: dập lửa.

Usually, dập lửa is the more natural choice for an actual fire.

Why:

• tắt is often used for things like lights, machines, engines, or flames going out
• dập suggests actively extinguishing a fire

So:

• dập lửa = put out a fire
• tắt đèn = turn off the light

You may hear lửa tắt for the fire goes out, but for the action of extinguishing it, dập lửa is the standard phrase.

Trước khi means before and introduces another action or event.

Structure:

• trước khi + verb/clause

So:

• trước khi đi = before going / before leaving

A key point for English speakers: Vietnamese verbs do not change form here. There is no equivalent of going, to go, or goes. The verb simply stays đi.

Examples:

• Rửa tay trước khi ăn. = Wash your hands before eating.
• Tắt đèn trước khi ngủ. = Turn off the light before sleeping.

Here, đi most naturally means go or leave, depending on context.

In English, this sentence is often best understood as:

• Put out the fire before you leave or
• Put out the fire before going

If the speaker is talking to someone who is about to depart from the current place, leave is usually the best translation.

Vietnamese often puts:

1. the main action first
2. then the time condition or time clause

So:

• dập lửa = main action
• trước khi đi = before leaving

This order is very natural.

You can also move the time phrase to the front for emphasis:

• Trước khi đi, hãy dập lửa.

That means the same thing, but it highlights before leaving a bit more.

Yes, it is correct and natural, but hãy makes it sound a little formal or instructional.

In everyday speech, people might say:

• Dập lửa trước khi đi nhé.
• Nhớ dập lửa trước khi đi.
• Trước khi đi, nhớ dập lửa.

These sound more conversational.

Very roughly:

• hãy = more formal instruction
• nhớ = remember to...
• nhé = softens the command and makes it friendlier

Vietnamese does not use articles the same way English does. There is no direct equivalent of a/an/the that must appear before nouns in most sentences.

So lửa can mean:

• fire
• the fire
• a fire

The exact meaning depends on context.

In this sentence, the context makes it clear that it means the fire that is relevant in the situation.

Yes. With hãy, the sentence can sound like:

• a direct instruction
• a safety reminder
• a general rule

So it could be said to one person in one situation, or it could appear on a sign or in safety instructions.

That is another reason hãy sounds slightly more formal than plain everyday speech.