The character can cast a spell with a casting time of 1 action as a standard action.
A spell that takes 1 full round to cast is a full-round action. It comes into effect just before the beginning of the character's turn in the round after the character began casting the spell. The character then acts normally after the spell is completed. A spell that takes 1 minute to cast comes into effect just before the character's turn 1 minute later (and for each of those 10 rounds, the character is casting a spell as a full-round action).
The character must make all pertinent decisions about a spell (range, target, area, effect, version, etc.) when the character begins casting.