YOU SAID:
their eyes couldn't believe it
INTO JAPANESE
彼らの目はそれを信じられなかった
BACK INTO ENGLISH
Their eyes couldn't believe it.
INTO JAPANESE
彼らの目はそれを信じられなかった。
BACK INTO ENGLISH
Their eyes could not believe it.
INTO JAPANESE
彼らの目はそれを信じられなかった。
BACK INTO ENGLISH
Their eyes could not believe it.
That didn't even make that much sense in English.