Questions & Answers about Jag är säker på att han sov igår morse.
Why does it say igår morse instead of igår morgon?
In Swedish, to say "yesterday morning", you combine igår (yesterday) with morse. The word morse is a special form of the word for "morning" that is only used in fixed past-tense time phrases like igår morse (yesterday morning) and i morse (this morning). You cannot say igår morgon.
The lesson is about time expressions with i. Where is the i here?
It is built right into the word igår! You will often see it written as two separate words, i går, which literally means "in yesterday". So the phrase i går morse (or igår morse) uses the preposition i to talk about a specific time in the past.
Why is there a på after säker? Can I just say Jag är säker att...?
In Swedish, you need the preposition på here. The phrase for "to be sure about" or "to be sure that" is att vara säker på. It is a fixed expression you will just have to memorize, so whenever you say you are sure of something, always include på.
What kind of verb is sov?