"As light as a bird flies by" There was a man from Chen She in Bianjing in the Northern Song Dynasty. He accidentally got an old copy of "The Collected Poems of Du Fu", and he felt like he had found a treasure. However, due to poor storage of this book, the words in many poems have fallen off. Once, when Chen Sheren was reading "Poem to Send Captain Cai", he found that there was a missing word after the word "bird" in the sentence "The body is as light as a bird, but the gun is so urgent that thousands of people call". He thought about it repeatedly, but could not make a conclusion. What is that word? One day, when he was discussing poetry with several poetry friends, he raised this question and hoped that everyone could fill in the most appropriate word. Someone wrote the word "ji", thinking that the word "ji" best expresses Cai Duwei's brisk and quick vertical jumping skills. Some people think it is not good because the word "ji" in the first sentence and the word "ji" in the next sentence are too close in pronunciation and meaning, and seem a bit repetitive. Someone else wrote the word "degree", but Chen Sheren thought that the word "degree" seemed too blunt when used here, and it did not show the characteristics of being as light as a bird. Some people even suggested using words such as "fall", "rise" and "下", but no one was satisfied. Later, Chen Sheren found a relatively complete "Collection of Du Fu's Poems" elsewhere. When he opened the "Poems for Cai Duwei", it turned out that the sentence was "A bird flies by because of his light body." It is indeed appropriate to use the word "guo" to describe Cai Duwei's jumping high and fast, like a bird flying in front of his eyes.