Learn Hardcore Danish: Jeg havde glemt nøglen, så min søster måtte komme med den. - I had forgotten the key, so my sister had to bring it.

The pluperfect havde glemt shows that the forgetting happened earlier than the next past event (the sister having to come). You could also say Jeg glemte nøglen, så min søster måtte komme med den, which is fine as a simple past narrative; havde glemt just highlights the sequence more clearly.

What exactly does måtte mean here—permission or necessity?

Here måtte means necessity: had to. It’s the past of må and can mean either “may/allowed to” or “must/has to” depending on context. Synonyms for necessity: var nødt til at or, sometimes, skulle (obligation/plan). Forms: må – måtte – måttet.

Why is there no at before komme after måtte?

Danish modal verbs (e.g., kan, vil, skal, må, bør, tør) take a bare infinitive, so you say måtte komme, not måtte at komme.

Why say komme med den to mean “bring it”? Isn’t there a verb bringe?

komme med (noget) = “come with (something)” → “bring (to where I am)”, receiver’s perspective.
tage (noget) med = “take (something) along”, sender/Carrier’s perspective.
bringe exists but is more formal/bookish. All are possible here: måtte komme med den / måtte tage den med / måtte bringe den (slight style/pragmatic nuances).

Why is the pronoun den and not det?

Because nøgle is common gender (en nøgle), so the 3rd‑person singular pronoun is den. Neuter nouns (et-words) take det. Example: et kort … så hun måtte komme med det.

Could I use denne instead of den?

No. denne means “this (one)” and points deictically; here you just refer back to a previously mentioned noun, so the simple pronoun den is correct.

Why use nøglen (the key) instead of min nøgle (my key)? Are both possible?

Both are possible. nøglen treats it as a specific, context-known key; min nøgle emphasizes possession. With possessives you don’t add the definite suffix, so not min nøglen, but min nøgle.

Does så require a comma, and does it cause inversion?

Comma: It’s common to put a comma before så when it links two main clauses.
Inversion: As a coordinating conjunction, så doesn’t itself force inversion; the second clause still has normal main‑clause V2 order: min søster (1) måtte (2). If så is used as a sentence adverb meaning “then/therefore”, you’ll see inversion: …, så måtte min søster ….

Why is the auxiliary havde used, not var?

Most verbs use have in the perfect tenses. være is used mainly with intransitive verbs of movement or change of state (e.g., komme, gå, blive): jeg var kommet, but jeg havde glemt.

Can I drop med den and say just …, så min søster måtte komme?

That would mean “had to come” without specifying she brought the key. If the key is the crucial item, keep med den to convey “bring it.”

How would the sentence look if I started with the reason?

Fordi jeg havde glemt nøglen, måtte min søster komme med den. A fronted subordinate clause (fordi…) occupies first position, so the following main clause inverts: måtte comes before min søster (still verb‑second overall).

Is there a difference between måtte komme and simply kom?

Yes. kom states the fact that she came; måtte komme expresses necessity (she had no choice) and usually implies she then did so as the solution.

Can I say var nødt til at komme instead of måtte komme?

Yes: …, så min søster var nødt til at komme med den. It often sounds a bit stronger/more explicit than måtte.

What are the gender and forms of nøgle?

Common gender:

singular: en nøgle, definite: nøglen
plural: nøgler, definite plural: nøglerne Pronouns: singular common → den; plural → dem (e.g., …, så hun måtte komme med dem for “the keys”).

Could I replace så with derfor or og?

derfor = “therefore”: Jeg havde glemt nøglen; derfor måtte min søster komme med den. Note inversion after derfor: måtte min søster.
og = “and”: …, og min søster måtte komme med den. Grammatically fine, but weaker on cause–effect than så.

Quick pronunciation tips for the tricky words?

nøglen: ø is like French “œ”; the g before l is soft (y‑like). Roughly “NOY-len.”
måtte: short å (like the o in “off,” shorter); double tt keeps the vowel short. Roughly “MOT-eh.”