I would make a couple of corrections: First, you need the possessive (cousin's). Second, you need to complete the comparison correctly (Not only/ but also). As a child, I thought that when I slept at my cousin's house, it was a game.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
Doctor DVery well, then say:As a child, I thought that when I slept at my cousin's house, it was a game. Now, as an adult, I know that day was indeed a game; nevertheless, it was also an adventure.Does that work for you?Yes. Thank you