Learn Hardcore Norwegian: Du må møte opp på kontoret i morgen.

In Norwegian, the subject is normally required in a full sentence, so you usually keep du. Dropping it would sound incomplete except in very informal notes, commands, or bullet points.
So Du må … is the standard way to say it.

What exactly does må mean here, and how strong is it?

Må is the modal verb meaning must / have to. It expresses obligation or necessity and is generally strong—closer to “must” than “should.”
Depending on context it can be strict (a requirement) or practical necessity (“you’ll need to”).

Why is the verb order Du må møte … and not something like Du møter må …?

Modal verbs in Norwegian typically take an infinitive verb after them:

må + infinitive → må møte (must meet / must show up)
So møte stays in the infinitive form after må.

What does møte opp mean, and why are there two words?

Møte opp is a common verb phrase meaning to show up / report in person / turn up.

møte = to meet / to attend
opp adds the sense of turning up (physically arriving)
You’ll often see this with places and times: møte opp på kontoret klokka 9.

Can I say just møte without opp?

Sometimes, yes, but the meaning may shift.

møte opp strongly emphasizes showing up (arriving).
møte alone can mean meet (someone) or attend, and may sound less like a “report there in person” instruction.
In this sentence, møte opp is the natural choice.

Why is it på kontoret and not i kontoret?

With workplaces/institutions, Norwegian often uses på where English might say “in/at.” På kontoret is the idiomatic way to mean at the office (the office as a place of work).
I kontoret sounds more like being inside a particular office room (physical interior), and is less common in this “go to work” sense.

Why does Norwegian use i morgen and not something like på morgenen?

I morgen means tomorrow (the whole day).
På morgenen means in the morning (time of day), and would normally be paired with a day if needed: i morgen tidlig / i morgen om morgenen.
So i morgen is correct for “tomorrow.”

Where do time and place usually go in Norwegian word order?

A common pattern is: verb(s) + place + time (though it’s flexible). This sentence follows that:
må møte opp (verbs) + på kontoret (place) + i morgen (time).
You can also front time for emphasis: I morgen må du møte opp på kontoret.

If I start with I morgen, why does the word order change?

Norwegian is a V2 language: in main clauses, the finite verb is in the second position. If you move I morgen to the front, it takes the first position, so må must stay second:

Du må møte opp på kontoret i morgen.
I morgen må du møte opp på kontoret.
Notice du comes after må in the second version.

Is kontoret definite, and why does it have -et?

Yes—kontoret is the definite form of kontor (an -et neuter noun).

et kontor = an office
kontoret = the office
In “at the office” contexts, Norwegian often uses the definite form: på kontoret.

Could I replace du with De for politeness?

Grammatically yes: De må møte opp på kontoret i morgen.
But in modern Norwegian, De (formal “you”) is relatively rare and can sound very formal or old-fashioned. Many workplaces still use du even in polite situations.

How would this sentence change in the past or future?

Past obligation: Du måtte møte opp på kontoret i går. (had to)
Future is often expressed with present + time adverbial (as here), or with skal for planned/expected actions:
- Du må møte opp … i morgen. (obligation)
- Du skal møte opp … i morgen. (you are supposed to / you’re to)