长短句交替（英文：Epode）是一首奥德诗中的第三部分。该格律形式由品达等一些诗人确立。在古希腊，随着合唱抒情诗的演变，新的诗歌形式应运而生，也就是长短句交替。

Epode, in verse, is the third part of an ode, which followed the strophe and the antistrophe, and completed the movement.

At a certain point in time the choirs, which had previously chanted to right of the altar or stage, and then to left of it, combined and sang in unison, or permitted the coryphaeus to sing for them all, while standing in the centre. With the appearance of Stesichorus and the evolution of choral lyric, a learned and artificial kind of poetry began to be cultivated in Greece, and a new form, the epode-song, came into existence. It consisted of a verse of iambic trimeter, followed by a verse of iambic dimeter, and it is reported that, although the epode was carried to its highest perfection by Stesichorus, an earlier poet, Archilochus, was really the inventor of this form.