1) It was my birthday, so I ate beef with my friends.
2) It was [sirloin], and although the marbling wasn't very good, the meat quality was good and it was delicious.
3) I had a glass of [sake] that I bought on my last trip to Japan.
4) I drank sweet potato soju when eating galbi.
5) It was fun meeting friends for the first time in a while and spending my birthday together!