Breakdown of Du darfst das Brot nicht essen, weil es nicht glutenfrei ist.
sein
to be
du
you (informal singular)
es
it
essen
to eat
Questions & Answers about Du darfst das Brot nicht essen, weil es nicht glutenfrei ist.
Why is nicht placed right before essen in the first half of the sentence?
When a sentence has a modal verb (darfst) and an infinitive (essen), nicht goes right before the infinitive at the end of the clause to negate the entire action. It tells us exactly what the prohibited action is: eating the bread.
Why is the second nicht placed right in front of glutenfrei?
In the second clause, nicht is specifically negating the adjective glutenfrei (gluten-free). When you want to negate a specific adjective or adverb rather than the whole sentence, you put nicht directly in front of it.
Doesn't darfst mean "may" or "allowed to"? Why does the English translation say "must not"?
You are right that dürfen means "to be allowed to". However, when you negate it (nicht dürfen), it means you are not allowed to do something, which translates most naturally to English as "must not". If you wanted to say "do not have to", you would use nicht müssen.
As a quick refresher, why does the verb ist go at the very end of the second clause?
The conjunction weil (because) always introduces a subordinate clause. In German, subordinate clauses push the conjugated verb (in this case, ist) all the way to the end of that clause.