In die bocht moeten we langzamer rijden, want op de rotonde letten auto’s niet altijd goed op.

Because Dutch main clauses usually follow the verb-second (V2) rule. The first slot is taken by In die bocht, so the conjugated verb moeten has to come next, and the subject we comes after it.

Basic pattern:

In die bocht + moeten + we + ...

If the sentence started with the subject, you would get:

We moeten in die bocht langzamer rijden.

Both are correct; the original just emphasizes in that bend first.

Die is a demonstrative word, meaning that or that particular.

So die bocht = that bend / that curve.

It is die because bocht is a de-word:

• de bocht
• die bocht

If it were a het-word, you would usually get dat instead.

Langzamer is the comparative form: slower / more slowly.

So:

• langzaam rijden = drive slowly
• langzamer rijden = drive more slowly / slower

In this sentence, langzamer suggests slower than usual or slower than we might otherwise drive. That sounds very natural here.

Because moeten is a modal verb, and in Dutch the main verb usually stays in the infinitive at the end of the clause.

So:

• we moeten rijden
• we moeten langzamer rijden

This is very common with verbs like:

• moeten
• kunnen
• willen
• mogen
• zullen

Because Dutch uses different fixed prepositions with different places.

• in een bocht = in a bend / on a curve
• op een rotonde = on a roundabout

This is not something you can always translate word-for-word from English. It is mostly a matter of normal Dutch usage, so it is best to learn the noun together with its usual preposition.

Want means because, but it is a coordinating conjunction. That means the word order after it stays like a normal main clause:

..., want op de rotonde letten auto’s niet altijd goed op.

If you used omdat, the word order would change because omdat is a subordinating conjunction. For example:

..., omdat auto’s op de rotonde niet altijd goed opletten.

So the difference is not just meaning; it also affects word order.

Because opletten is a separable verb.

Its full form is opletten = to pay attention.
But in a main clause, the prefix often separates:

• Ik let op.
• Auto’s letten niet goed op.

In an infinitive or subordinate clause, it usually stays together:

• Je moet goed opletten.
• ..., omdat auto’s niet altijd goed opletten.

This is a very common Dutch pattern.

This is the natural Dutch order in this sentence.

• niet altijd = not always
• goed opletten = pay good/proper attention

Because opletten is split, the op goes to the end, so goed appears before that final particle.

So:

• auto’s letten niet altijd goed op

means:

• they do not always pay attention properly

If you changed the order, the sentence would sound less natural or could change the meaning.

Literally, yes, it says cars, but in normal Dutch this often refers to the people in them: drivers / motorists.

English does this too sometimes, for example:

• The car in front of me suddenly stopped

You usually mean the driver of that car, not the machine itself making a decision.

So here auto’s is a natural shorthand for people driving cars.

Because many Dutch nouns ending in a vowel form the plural with ’s.

So:

• auto → auto’s
• taxi → taxi’s

The apostrophe helps keep the pronunciation clear. Without it, the spelling would look odd and could suggest a different pronunciation.

Yes, absolutely.

That version is also correct:

• We moeten in die bocht langzamer rijden.

The difference is mainly emphasis.

• In die bocht moeten we langzamer rijden puts focus on that bend
• We moeten in die bocht langzamer rijden starts more neutrally with we

Dutch often moves parts of the sentence to the first position to highlight them, but the verb still stays in second position.