Learn Swedish: Hunden är inte van vid den stora katten. - The dog is not used to the big cat.

The phrase for 'accustomed to' in Swedish is van vid. Prepositions rarely translate word-for-word between English and Swedish, so it is best to memorize van vid as a fixed phrase.

I learned that 'used to' is brukar. Why can't we use brukar here?

Brukar means 'usually do' or refers to a past habit, and it is always followed by a verb. When 'used to' means 'accustomed to' a noun (like the cat), you must use the adjective phrase vara van vid.

Why is it den stora katten and not just stora katten?

Swedish uses a pattern called the 'double definite' when a specific noun has an adjective. You need the standalone article (den), the adjective with its -a ending (stora), and the definite ending attached to the noun (katten).

If this lesson is about general statements, why don't we drop the articles here?

Because this sentence is about a specific dog and a specific cat, not dogs and cats in general. If we wanted to make a general statement, we would use the plural indefinite without articles: Hundar är inte vana vid stora katter.