This sentence shows the unique frontier battlefield scenery. At first glance, it is the application of fu method: on the continuous Yanshan mountains, a bright moon is in the sky; Wan Li in Pingsha looks like a layer of white frost and snow in the moonlight. This ordinary person may only feel sad and cold battlefield scene, which has unusual attraction for those who are determined to serve the country. The Moon in Yanshan Mountain is Like a Hook, and Xiao Yue hangs a jade bow as a curtain (the sixth in Nanyuan). "Hook" is a machete, and both are weapons. It is associated with the image of weapons from the bright crescent moon, which means thinking about fighting. Zhenyuan, Yuanhe period, where the author lived, was a period when the buffer region was extremely domineering, and the Jimen area in Youzhou implied by "Yanshan Mountain" was the zone where the buffer region ravaged for the longest time and caused the most disasters, so the poems were quite realistic. Thinking about war is also targeted. Sha Xue's flat battlefield is chilly, but it is a place where heroes can play. So these two sentences are lyrical and tangible.