It's a longish poem, not in your anthology, but you can find it in The Complete Yeats, and I've given you on this handout page just a couple stanzas from it, so you have a sense of it.

这是一首很长的诗，你们的选集里没有，但在叶芝全集里可以找到，我给你们发的材料上就有,只是其中的几节，你们可以大概有个了解。

耶鲁公开课 - 现代诗歌课程节选