YOU SAID:
The reason why I was unable to join you was because my plans were already full
INTO JAPANESE
私があなたに加わることができなかった理由は私の計画がすでにいっぱいだったからです
BACK INTO ENGLISH
The reason why I could not join you is because my plan was already full
INTO JAPANESE
私があなたに加わることができなかった理由は私の計画がすでにいっぱいだったからです
BACK INTO ENGLISH
The reason why I could not join you is because my plan was already full
That didn't even make that much sense in English.