So, what would be "I am reading IN an hour"? I would've said "jeg leser i en time"...
"Jeg [leser/skal lese] om en time".
Bare hyggelig! :)
Why is "Jeg leser for en time" not correct?
Prepositions don't always translate directly. 'for' = 'i' in this context (time).
why I can't use om?
Because that would change the meaning of the sentence (see PunkyTaurus' post and my response above).