Learn Swedish: Hyran ska betalas i förskott. - The rent must be paid in advance.

While you usually learn ska as a future tense marker meaning "will" or "going to", in official rules, contracts, and instructions, it expresses a strong obligation or requirement, much like "must" or "shall" in English. Therefore, ska betalas means "must be paid".

Why does the verb betala have an -s at the end in this sentence?

The -s creates the passive voice (known as the s-passive). Because the rent isn't paying for something itself, but rather is being paid by someone, we use the passive. After the modal verb ska, the main verb stays in its infinitive form betala, and we just add an -s to make it betalas (to be paid).

How does the phrase i förskott work?

The phrase i förskott is a fixed expression meaning "in advance". The noun förskott combines the prefix för- (pre- or before) and skott (which is related to sending or pushing forward, stemming from the verb skjuta). It paints a picture of sending the money ahead of time.

What is the opposite of i förskott if a payment is made late or afterwards?