One of the labors of reading Paradise Lost is the reader's obligation to supply the analog for the X, and this poem is filled with such X's.

读的一个麻烦就是,读者需要自行类比出X究竟是什么，偏偏诗中又充满了这种不确定物。

耶鲁公开课 - 弥尔顿课程节选