导言是文章的首段，应达到一下几个目的。

The introduction is the first paragraph in your essay, and it should accomplish a few specific goals.

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从首段出发之日起至最后停留点不少于3天。

Travel from Last stopover must commence no earlier than 3 days after departure from fare origin.

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到2015年，该数字坠入谷底至500。--首段描述数据。

The figure reached its bottom at 500 in the year of 2015.

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And so when the figure of Orpheus appears in this poem, it's the second half of the Orpheus story that Milton is forced to tell.

因此当俄耳甫斯的形象出现在这首诗中时，弥尔顿要讲的是他生平的后一段。

耶鲁公开课 - 弥尔顿课程节选

Now I believe that music works a magical potion, a magical spell on us.

我相信这首曲子就像一剂魔药,一段施在我们身上的符咒

耶鲁公开课 - 聆听音乐课程节选

Look at the last stanza.

看这首诗的最后一段。

耶鲁公开课 - 弥尔顿课程节选