These are drives that the poem seems to be struggling to keep in check, or that Milton is representing the poem as struggling to keep in check, or to purge in some way.

这就是促使诗歌努力去抑制竞争，或者弥尔顿代表诗歌去抑制竞争，或以某些方式去净化。

耶鲁公开课 - 弥尔顿课程节选