5

5a: 1 — B (special), 2 — C (event), 3 — D (hold), 4 — A (depends), 5 — A (formal), 6 — C (choose), 7 — C (remember).

5b: I enjoyed my birthday party. It was held in a café last summer. My family and friends were there. We ate pizza, played games and listened to music. I felt very happy.