What ancient poems describe lovers' constancy?

Ask the world, what is love, teach life and death? Flying in all directions, the old wings have been hot and cold several times. Have fun, leave the bitterness, and there will be more children in school. You should have a sentence, Wan Liyun, Qian Shan Dusk, who is the only shadow?

Cross grave road, flute and drum when lonely, smoke is still flat. What's the point of evocation? Shan Gui secretly calls the shots. The sky is also jealous. If you don't believe it, birds and swallows are all loess. For generations, leave it to poets to sing, drink and visit Qiu Yan.