The former housekeeper still keeps the keys to her former employers.

former 是形容词，意思是"以前的、从前的"，用来描述过去的状态或身份。在这个句子中，former 修饰 housekeeper 和 employers，表示"以前的管家"和"以前的雇主"。 former 也可以作为名词，表示"前者"，与"后者"(latter)相对。