Okay, in an earlier question, it's correct to say "jag har försökt ringa dig", leaving out the "att" for att ringa. Why is it correct in that sentence, but in this sentence you must have the att for att simma?
I wrote "tvungit" rather than "tvingat". Should that be accepted, or is it outright wrong, or just not in common use anymore? (I can tell from the number of google hits that tvingat is a lot more common, so maybe the latter?)