Решение:
Объясняем причины событий.
- a) All children's presents were food because it was a picnic-themed party.
- b) Slow didn't come on time (вовремя) because he got stuck in traffic.
- c) It was a very merry birthday because everyone had fun and enjoyed the celebration.
Ответ: a) because it was a picnic-themed party; b) because he got stuck in traffic; c) because everyone had fun and enjoyed the celebration.