Read the poem Jia Xu, think about the scenery described in the poem, and briefly analyze the functions of these scenery.

This poem describes the early morning in late autumn, and the green reeds along the river are covered with stale scenes, giving people a bleak and cold feeling. It not only creates a sad atmosphere, but also sets off the tragic feelings of the protagonist. This poem also describes the long and steep road along the river, the terrain is getting higher and higher, and the winding scene highlights the protagonist's sincere and persistent pursuit of the right person.