Learn Swedish: Måste jag deklarera den här klockan i tullen? - Do I have to declare this watch at customs?

In Swedish, demonstratives like den här (this) and den där (that) must be followed by a noun in its definite form. This is known as the double definite rule. Since you are pointing out a specific watch, both the demonstrative and the noun take a definite form.

Why do we use the preposition i in i tullen for 'at customs'?

While English uses 'at' for checkpoints, Swedish often uses i (in) for physical zones or institutions you pass through. You are considered to be physically inside the customs area, so it becomes i tullen.

Is deklarera only used for declaring goods at the border?

Not at all! While it perfectly translates 'declare' for customs, its most common everyday use in Sweden is for filing your annual income tax return. If a Swede says they need to deklarera, they are usually talking about their taxes.

Since this lesson is about varifrån, how would a customs officer ask where this watch came from?

They would likely ask Varifrån kommer den här klockan? (Where does this watch come from?). Varifrån neatly combines var (where) and ifrån (from) into a single interrogative adverb placed at the start of the question.