Learn Swedish: Regeringen ska ha byggt basen för tefaten. - The government reportedly built the base for the saucers.

The modal verb ska is frequently used in Swedish news and conversation to express hearsay or unverified claims, acting just like 'reportedly' or 'is said to' in English. To talk about an unverified event in the past, we combine ska with ha and the supinum form of the main verb, giving us ska ha byggt (is said to have built).

Is tefat the normal word for a UFO in Swedish?

Yes! Just like in English, a UFO is colloquially called a flying saucer. In Swedish, this is a literal translation: ett tefat means a tea saucer (from te and fat). The phrase for flying saucer is ett flygande tefat, but it is often shortened to just tefat. The form tefaten is the definite plural (the saucers).

Could I use the simple past tense byggde instead of byggt here?

No, you must use the supinum form byggt. A very common mistake is mixing up the simple past and the supinum. Because the verb directly follows ha (have), even inside a longer chain of modal verbs like ska ha, Swedish strictly requires the supinum form.

Why do we use the definite forms basen and tefaten?