YOU SAID:

But they still haven't joined the war.

INTO JAPANESE

しかし、彼らはまだ戦争に参加していません。

BACK INTO ENGLISH

However, they are not yet joined the war.

INTO JAPANESE

しかし、彼らはまだ戦争に参加しました。

BACK INTO ENGLISH

However, they still took part in the war.

INTO JAPANESE

しかし、彼らはまだ戦争に参加をしました。

BACK INTO ENGLISH

However, they still made a join war.

INTO JAPANESE

しかし、彼らはまだ結合の戦争をしました。

BACK INTO ENGLISH

However, they still made a join war.