Der er ikke meget benzin tilbage, så vi må finde en tankstation, før vi når broen.

Der er is the standard Danish way to say that something exists or is present, just like there is / there are in English.

So:

• Der er ikke meget benzin tilbage = There isn’t much petrol left

Here, der does not mean a specific place like there sometimes does in English. It is a grammatical placeholder.

Because benzin is an uncountable noun, like petrol, water, or money in English.

In Danish:

• meget = much, a lot of, used with uncountable nouns
• mange = many, used with countable plural nouns

So:

• ikke meget benzin = not much petrol
• ikke mange biler = not many cars

Since you cannot normally count benzin as separate items, meget is the correct choice.

Tilbage means left or remaining.

So:

• Der er ikke meget benzin tilbage = There isn’t much petrol left

It often appears after the noun or quantity it relates to:

• Der er lidt tid tilbage = There is a little time left
• Har du penge tilbage? = Do you have money left?

In this sentence, tilbage tells us that the amount of petrol remaining is small.

Here så means so, in the sense of therefore or as a result.

The structure is:

• Der er ikke meget benzin tilbage, så vi må finde en tankstation
  = There isn’t much petrol left, so we have to find a gas station

It connects the first idea to the consequence.

Må is the present tense of at måtte, and here it means must / have to / need to.

So:

• vi må finde en tankstation = we must / have to find a gas station

Depending on context, må can also mean:

• may / be allowed to
• must / have to
• sometimes a logical must as in That must be true

In this sentence, it clearly expresses necessity.

En tankstation means a gas station, while tankstationen means the gas station.

Here, the speaker is talking about any suitable gas station, not a specific one already known to both speakers. That is why the indefinite form is used:

• en tankstation = a gas station
• tankstationen = the gas station

After modal verbs such as kan, vil, skal, må, bør, Danish normally uses the bare infinitive without at.

So:

• vi må finde = we must find
• jeg kan svømme = I can swim
• hun vil rejse = she wants to travel

You would only use at in other structures, not after a modal verb like må.

Før means before.

So:

• før vi når broen = before we reach the bridge

It introduces a subordinate clause about time.

Compare:

• før vi spiser = before we eat
• før han kommer = before he arrives

This is a very common point of confusion. Danish når can be either:

1. the verb at nå = to reach
2. the conjunction når = when

In før vi når broen, it is the verb:

• vi når = we reach
• broen = the bridge

So the clause means before we reach the bridge, not before we when the bridge.

The infinitive is at nå:

• Vi skal nå toget = We need to catch/reach the train
• Kan du nå det? = Can you reach/manage it?

In Danish, the definite article is often attached to the end of the noun.

So:

• en bro = a bridge
• broen = the bridge

This is one of the big differences from English. Instead of a separate word like the, Danish often adds a suffix:

• en bil → bilen
• en station → stationen
• et hus → huset

So broen simply means the bridge.

Because før introduces a subordinate clause, and Danish subordinate clauses normally keep the subject before the verb unless another rule changes the order.

So:

• før vi når broen = before we reach the bridge

This is the normal order:

• conjunction + subject + verb + object

Compare:

• når han kommer = when he comes
• fordi vi mangler tid = because we lack time

A useful contrast:

• Main clause: Vi når broen snart
• Subordinate clause: før vi når broen

The clause here is very straightforward: vi is the subject, når is the verb, and broen is the object.

Danish often uses the present tense to talk about the future, especially after time words like før, når, efter, and inden.

So:

• før vi når broen literally uses present tense, but in English we also usually say before we reach the bridge, not before we will reach the bridge

This is normal in both languages in many time clauses.

Other examples:

• Når jeg kommer hjem, spiser jeg = When I get home, I’ll eat
• Før hun går, taler vi med hende = Before she leaves, we’ll speak with her

So the present tense here is completely natural.

Yes, but the meaning and usage change a little.

• benzin = petrol / gasoline specifically
• brændstof = fuel in a broader sense
• gas in Danish usually means gas, not gasoline

So if you mean fuel for a normal petrol car, benzin is very natural.
A native English speaker should be careful not to assume Danish gas means gasoline the way it often does in American English.

Yes, in standard Danish punctuation, a comma is normally used to separate clauses here.

The sentence has two main clauses:

• Der er ikke meget benzin tilbage
• så vi må finde en tankstation

Then there is also the subordinate clause:

• før vi når broen

Danish comma rules are generally stricter than English ones, so learners often notice commas appearing where English might be more flexible.