Idiom
beyond your ken - 超过你的认知范畴
ken - the range of perception, understanding or knowledge
Sheldon: Woman, you're playing with forces beyond your ken.
Penny: Yeah, your ken can kiss my Barbie.
Penny想要气气Sheldon，她故意把ken曲解成玩偶，说：你的ken可以和我芭比娃娃谈恋爱。
a rule of thumb - 经验法则。见柯林斯词典。