Wir brauchen heute nicht noch einmal zu tanken, weil noch genug Benzin im Auto ist.

Because brauchen can mean to need to when it is followed by zu + infinitive.

• wir brauchen zu tanken = we need to refuel
• wir brauchen nicht zu tanken = we do not need to refuel

In modern German, this pattern is especially common in negative sentences like this one.

So:

• Wir brauchen heute nicht noch einmal zu tanken
  = We do not need to refuel again today.

Yes, this is an important difference.

• nicht brauchen zu = do not need to
• nicht müssen = also often do not have to

So in many situations, these are close in meaning:

• Wir brauchen heute nicht zu tanken
• Wir müssen heute nicht tanken

Both can mean We don’t need to refuel today.

But learners should be careful:

• müssen by itself means must
• nicht müssen means do not have to
• brauchen with nicht naturally expresses lack of necessity

So nicht brauchen zu is a very direct way to say that something is unnecessary.

Because zu tanken is an infinitive construction, and in German infinitives usually go toward the end of the clause.

The first clause is:

• Wir brauchen heute nicht noch einmal zu tanken

Its structure is roughly:

• Wir = subject
• brauchen = conjugated verb
• heute = time expression
• nicht = negation
• noch einmal = again / one more time
• zu tanken = infinitive phrase

German often places the conjugated verb early and the infinitive at the end.

tanken means to refuel, to fill up, or to get gas/petrol.

It is commonly used when talking about putting fuel into a vehicle.

Examples:

• Ich muss tanken. = I need to refuel.
• Wir tanken an der Tankstelle. = We refuel at the gas station.

In this sentence, no direct object is needed because it is already clear that the car is being refueled.

Both can often mean again, but noch einmal emphasizes one more time / another time a bit more clearly.

• noch einmal = one more time, again
• wieder = again

Here, nicht noch einmal tanken suggests:

• we already fueled up before, and
• we do not need to do it one more time today

So noch einmal fits very naturally.

A similar version with wieder would also be possible in many contexts:

• Wir brauchen heute nicht wieder zu tanken.

But noch einmal sounds especially clear for another time.

German word order is flexible, but there are common patterns.

In a main clause, the conjugated verb is in second position:

• Wir brauchen heute nicht noch einmal zu tanken

Here:

1. Wir = first position
2. brauchen = second position

After that, adverbs like heute can appear. Putting heute here is very natural.

You could also move heute to the front for emphasis:

• Heute brauchen wir nicht noch einmal zu tanken.

That would still be correct.

Because weil introduces a subordinate clause, and in German subordinate clauses the conjugated verb normally goes to the end.

Main clause:

• Wir brauchen heute nicht noch einmal zu tanken

Subordinate clause:

• weil noch genug Benzin im Auto ist

Notice that ist comes at the end.

This is one of the most important German word order rules:

• weil
  • ... + verb at the end

Example:

• Ich bleibe zu Hause, weil ich müde bin.

Here noch means still.

So:

• noch genug Benzin = still enough gasoline/petrol

The idea is that the car still has a sufficient amount of fuel left.

Compare:

• genug Benzin = enough fuel
• noch genug Benzin = still enough fuel

So noch adds the sense that the fuel is still there at this moment.

im is a contraction of in dem.

• in dem Auto → im Auto

This is very common in German.

Here, im Auto means in the car.

Why not in das Auto?

• in das Auto usually suggests movement into the car
• in dem Auto / im Auto describes location in the car

Since the fuel is located inside the car, German uses the location form:

• noch genug Benzin im Auto ist

German often uses mass nouns without an article when speaking in a general, unspecified way.

So:

• genug Benzin = enough gasoline/petrol

This works like English:

• enough fuel
• not usually enough the fuel

You could use an article in other contexts, but here it is not needed.

Because genug works here like a quantity word meaning enough.

• genug Benzin = enough fuel
• genug Geld = enough money
• genug Zeit = enough time

It comes before the noun it refers to.

So the phrase is built normally:

• noch genug Benzin

Yes, that is possible, but the word order would change.

With weil, the verb goes to the end:

• ..., weil noch genug Benzin im Auto ist.

With denn, the clause stays a normal main clause:

• ..., denn es ist noch genug Benzin im Auto.

So both can mean because, but:

• weil introduces a subordinate clause
• denn introduces a coordinating clause

Also, with denn, German usually sounds more complete with es:

• denn es ist noch genug Benzin im Auto

Yes. German main clauses are built around the verb in second position, not necessarily the subject first.

So the original is:

• Wir brauchen heute nicht noch einmal zu tanken.

But you could also say:

• Heute brauchen wir nicht noch einmal zu tanken.
• Noch einmal brauchen wir heute nicht zu tanken.

These versions change emphasis, but the conjugated verb brauchen still stays in second position.

So Wir first is simply the most neutral choice.