Complete the dramatic vampire's monologue.

I have been wandering these dark, lonely castle halls ___ three centuries, waiting for someone to return my favorite cape.

The correct answer is for.

Romance languages often use a single structure for both the starting point and the duration of an event (for example, desde hace in Spanish). In English, we use for to indicate a duration or length of time (like three centuries or ten minutes). We use since to indicate a specific starting point in the past (like since 1723 or since Tuesday).