背信弃义
Put the cart before the horse.
Turn topsy-turvy.
eg：Writing a book review before you have read the whole book is putting the cart before the horse.
中英俚语俗语来源：大学：“物有本末，事有终始。”
同义词：轻重倒置 Turn things upside down.
反义词：拨乱反正 Put things back to order.
