YOU SAID:

He must be playing with matches again.

INTO JAPANESE

彼はもう一度マッチで遊ぶ必要があります。

BACK INTO ENGLISH

He was once again playing with matches.

INTO JAPANESE

彼はもう一度マッチで遊んでいた。

BACK INTO ENGLISH

He was playing in the match again.

INTO JAPANESE

彼はもう一度マッチで遊んでいた。

BACK INTO ENGLISH

He was playing in the match again.