Vi må beslutte planen i dag.

må is the present‐tense form of the modal verb å måtte, which expresses obligation or necessity—equivalent to English must or have to.

• Part of speech: modal auxiliary
• Function: it modifies the following verb (beslutte) to show that deciding the plan is required
• Example: Jeg må gå (“I must go”)

Both are common modals, but they convey different shades of meaning:

• må = necessity/obligation (external or internal need)
  • “Du må levere rapporten i dag.” (“You must hand in the report today.”)
• skal = future intention, plan, promise or command in spoken language
  • “Jeg skal ringe deg senere.” (“I will call you later.”)
  • As a command (less formal than må): “Du skal være stille!” (“You shall/should be quiet!”)

After a modal verb like må, the main verb appears in the bare infinitive (without å). In Norwegian:

• Correct: Vi må beslutte planen.
• Incorrect: Vi må å beslutte planen.
  Compare with a normal (non‐modal) infinitive:
• Vi ønsker å beslutte planen. (“We wish to decide the plan.”)

Yes, both can mean “to decide,” but with subtle differences:

• beslutte
  • More formal, often implies a final decision after deliberation
  • Comparable to English “to resolve” or “to make a decision”
• bestemme
  • More everyday, can mean “to determine,” “to set,” or “to decide”
  • Eg: Vi bestemmer tid og sted (“We decide time and place.”)
  In many contexts they’re interchangeable, but beslutte carries a slightly more official tone.

planen = “the plan.” The definite form is used because the plan is specific or already known in context.

• If you were speaking about any plan (indefinite), you’d say en plan.
• Here, it’s “the plan we’ve been talking about” → planen.

i dag (“today”) is a time adverbial. Norwegian allows some flexibility, but you must respect the V2 rule: the finite verb (here må) must be the second element.

• End position (neutral): Vi må beslutte planen i dag.
• Initial position (time emphasis): I dag må vi beslutte planen. (Verb stays second, subject third.)
  Both are correct; choice depends on what you want to emphasize.