Greek是希腊人，me是我，Greek to me含义是“我完全无法理解、一窍不通”。

【例句】
Sorry, I don't understand what you said. It is Greek to me.
对不起，我不知道你说的是什么，我对那一窍不通。

She tried to explain how the system works, but it's all Greek to me.
她努力解释系统如何运作，可我怎么也弄不明白。