Questions & Answers about Er weiß, dass er die Allergie nicht hat.
Why is nicht placed right before hat in the second part of the sentence?
This lesson focuses on where to put nicht in complex sentences. In a subordinate clause (introduced here by dass), the conjugated verb (hat) is pushed to the very end. Because nicht is negating the entire action of having the allergy, its natural position is at the end of the clause, which places it directly in front of that final verb.
Why do we use nicht here instead of keine? Don't we use kein to negate nouns?
We use forms of kein to negate nouns with indefinite articles (like 'a' or 'an') or nouns with no articles. However, this sentence talks about a specific allergy: die Allergie (the allergy). To negate a noun that has a definite article (der, die, or das), you must use nicht. If the sentence meant that he didn't have any allergy at all, it would be dass er keine Allergie hat.
Why is there a comma before dass?
German strictly requires a comma between a main clause (Er weiß) and a subordinate clause (dass er die Allergie nicht hat). The word dass is a subordinating conjunction, which connects the two ideas and forces the conjugated verb (hat) to the end of its clause.
Why is the verb weiß spelled with an ei instead of an i like in its infinitive wissen?