Zorg jij ervoor dat de deur dicht is voordat we beginnen?

Because this is a yes/no question in Dutch. In a main-clause question, the finite verb usually comes first, and the subject comes after it.

• Statement: Jij zorgt ervoor dat de deur dicht is.
• Question: Zorg jij ervoor dat de deur dicht is?

In real usage, this kind of question often functions as a request rather than a genuine request for information. It can sound like: Will you make sure the door is closed?

Ervoor zorgen dat is a very common Dutch expression meaning to make sure that, to ensure that, or to see to it that.

It behaves like a fixed pattern:

• ervoor zorgen + dat-clause

Examples:

• Ik zorg ervoor dat alles klaar is.
• Zorg jij ervoor dat hij op tijd komt?

So in your sentence, you should learn ervoor zorgen dat as one useful chunk.

This is one of those very Dutch-looking structures. The er is part of a pronominal adverb: er + preposition.

Here, the preposition is voor, and together they make ervoor.

In ervoor zorgen dat ..., the er points forward to the content introduced by dat. In other words, Dutch does not just say zorgen voor dat here. It normally uses ervoor zorgen dat.

You will see the same kind of thing in other expressions:

• rekenen op → Ik reken erop dat...
• denken aan → Ik denk eraan dat...
• wachten op → Ik wacht erop.

So ervoor is not random; it is a normal Dutch structure.

Both are possible, but they are not exactly the same in feel.

• je is the usual unstressed form
• jij is the stressed form

So:

• Zorg je ervoor dat de deur dicht is...? = more neutral
• Zorg jij ervoor dat de deur dicht is...? = puts more emphasis on you

Using jij can suggest something like:

• Will you be the one to make sure of that?
• Can you take care of that?

A native speaker might choose jij to sound slightly more pointed or contrastive.

Because after dat, you are in a subordinate clause, and Dutch usually sends the conjugated verb toward the end of that clause.

So:

• Main clause: De deur is dicht.
• Subordinate clause: ... dat de deur dicht is.

This is one of the biggest word-order differences between English and Dutch.

A simple rule:

• main clause: verb usually in second position
• subordinate clause: verb usually at the end

For a door or window, dicht is very common and natural. It means shut/closed.

• De deur is dicht.
• Het raam is dicht.

You can also say gesloten, but that often sounds a bit more formal or more like closed as a state/result.

Compare:

• De deur is dicht. = everyday, very natural
• De deur is gesloten. = also correct, but slightly more formal

With shops, buildings, or services, gesloten is especially common:

• De winkel is gesloten.

So in this sentence, dicht is the normal everyday choice.

Because voordat is a fixed subordinating conjunction meaning before.

So you write:

• voordat we beginnen

not normally:

• voor dat we beginnen

As a conjunction, voordat introduces a subordinate clause, which is also why the verb beginnen goes to the end.

For the same reason as with dat de deur dicht is: voordat introduces a subordinate clause, and Dutch subordinate clauses usually place the verb at the end.

So:

• Main clause: We beginnen.
• Subordinate clause: voordat we beginnen

This is a very regular pattern in Dutch:

• als we beginnen
• omdat we beginnen
• voordat we beginnen

Grammatically, it is a question. But in actual communication, it often works as a polite request or instruction.

So the speaker is probably not wondering whether you are capable of doing it. They are asking you to take responsibility for it.

Compare the tone:

• Zorg ervoor dat de deur dicht is. = direct command
• Zorg jij ervoor dat de deur dicht is? = softer, more like a request
• Wil jij ervoor zorgen dat de deur dicht is? = also very common and polite

Yes. That is also correct, and it is very common.

Compare:

• Zorg dat de deur dicht is.
• Zorg ervoor dat de deur dicht is.

The version with ervoor is a bit fuller and more explicitly matches the fixed expression ervoor zorgen dat. The shorter version is often more direct and conversational.

In practice, both are natural Dutch.

Dutch comma use is often a bit lighter than English comma use. A comma before a final subordinate clause is not always required, especially when the sentence is short and easy to read.

So this is fine:

• Zorg jij ervoor dat de deur dicht is voordat we beginnen?

Some writers might add a comma for clarity in longer sentences, but here omitting it is completely normal.