The first paragraph, describing the legend and overall environment of Shu Dao, this paragraph. Is it "dangerous"? Is it difficult in heaven? Is it very high, like a high flag with six dragons driving the sun, and far below, the river beats its twisted channel violently? Have you been to such a high place? Even the yellow crane is difficult to reach. Is it 100% discount?
In the second paragraph, it is difficult to outline the environment that sets off the Shu Road. This one. We don't know whether this road to the west will never end. The road ahead is getting darker and darker. Looking ahead, there are waterfalls and rocks on the cliff.
The third paragraph describes the danger of sword gate, which sets off the difficulties of Shu Dao and expresses the author's feelings. This one. Although one person guards it, ten thousand people can't force it, if he is disloyal, but a wolf to his companion? .