YOU SAID:
My rats are so badly behaved.
INTO JAPANESE
私のネズミはとてもひどい振る舞いをしています。
BACK INTO ENGLISH
My mouse behaves very badly.
INTO JAPANESE
私のマウスは非常にひどい振る舞いをします。
BACK INTO ENGLISH
My mouse behaves very badly.
That didn't even make that much sense in English.