قبل از اینکه بروی، در را قفل کن.

It means before when it is followed by a clause.

So:

• قبل از = before
• اینکه helps introduce the following clause

In this sentence, قبل از اینکه بروی means before you go / before you leave.

A very literal breakdown would be something like before that you go, but you should learn قبل از اینکه as a natural Persian pattern.

Because after قبل از اینکه, Persian normally uses the subjunctive for an action that has not happened yet.

• بروی = you go / you leave in the subjunctive
• می‌روی = you go / are going in the indicative
• برو = go! as an imperative

So:

• قبل از اینکه بروی = before you go
• قبل از اینکه می‌روی is not the normal choice here
• قبل از اینکه برو would be wrong, because برو is a command

Yes, بروی sounds more standard written or careful spoken Persian.

In everyday conversation, many speakers would say:

• قبل از اینکه بری، در را قفل کن.

So:

• بروی = more formal / standard
• بری = more conversational

Both mean the same thing here.

Because Persian often drops subject pronouns when the verb already shows the person.

Here, both verbs point to you:

• بروی = you go
• کن = do / make in the command form, so you lock

So Persian does not need تو unless you want emphasis:

• قبل از اینکه تو بروی، در را قفل کن.

That is grammatical, but usually unnecessary.

را marks the direct object, especially a specific or known one.

So in:

• در را قفل کن

در is the thing being locked, and را marks it as the object of the verb.

A rough literal sense is:

• the door, lock it

English does not have an exact equivalent of را, so it is best to think of it as an object marker.

Because here در is followed by را, which tells you it is a noun phrase functioning as the object.

So:

• در را = the door
• prepositional در meaning in / at would not be followed by را in this way

For example:

• در خانه = in the house
• در را = the door

Context also makes it clear: you can lock a door, not lock in.

Yes. This is a compound verb, which is very common in Persian.

It is made of:

• قفل = lock
• کردن = to do / to make

Together:

• قفل کردن = to lock

So the imperative becomes:

• قفل کن = lock!

This is normal Persian structure. Many Persian verbs work like this:

• تمیز کردن = to clean
• باز کردن = to open
• خاموش کردن = to turn off

Yes. کن is the second-person singular informal imperative.

If you want to be polite or speak to more than one person, use:

• قبل از اینکه بروید، در را قفل کنید.

So:

• بروی / کن = singular informal
• بروید / کنید = plural or polite

Because Persian does not have a definite article like English the.

A noun like در can mean:

• a door
• the door

The exact meaning comes from context.

In this sentence, را and the situation make it clear that it means the door, meaning a specific door both speaker and listener know about.

Yes, absolutely.

You can say:

• قبل از رفتن، در را قفل کن.

That means essentially the same thing: Before leaving, lock the door.

The difference is mainly structure:

• قبل از اینکه بروی = before you go
• قبل از رفتن = before leaving

Both are natural.

Not completely, but the given order is very natural.

The sentence starts with the time clause:

• قبل از اینکه بروی

and then gives the command:

• در را قفل کن

You could also say:

• در را قبل از اینکه بروی قفل کن.

That is also understandable and grammatical.

Still, the original order feels very natural because Persian often puts the time/background information first.

A careful pronunciation would be close to:

• ghabl az inke beravi, dar râ qofl kon

In everyday speech, it may sound more like:

• ghabl az inke beri, daro qofl kon

A few useful notes:

• بروی is often reduced to بری in casual speech
• در را often sounds like درو or daro
• قفل may feel tricky to pronounce because of the consonant cluster

So if you hear a more relaxed spoken version, that is completely normal.