YOU SAID:
John ate cats for breakfast for a month and then killed his friend
INTO JAPANESE
ジョンは1か月間朝食に猫を食べ、その後友人を殺しました
BACK INTO ENGLISH
John ate a cat for breakfast for a month and then killed a friend
INTO JAPANESE
ジョンは猫を朝食に1か月間食べてから友人を殺しました
BACK INTO ENGLISH
John killed a friend after eating a cat for breakfast for a month
INTO JAPANESE
ジョンは朝食のために猫を一ヶ月食べた後に友人を殺しました
BACK INTO ENGLISH
John killed a friend after eating a cat for breakfast for a month
That didn't even make that much sense in English.