From the rules on casting spells:
"When you begin a spell that takes 1 round or longer to cast, you must continue the concentration from the current round to just before your turn in the next round (at least). If you lose concentration before the casting is complete, you lose the spell."
Exactly what does "you must continue the concentration" mean in this context? Can a spell caster who is continuing the concentration take other actions such as attacks of opportunity?
