Seven-character verse is a genre of China's traditional poetry, which has seven rhythms and modern style. It originated from the author of Qi Yongming's epoch-making phonology works in the Southern Dynasties, from Shen Quanqi and Song Wenzhi in the early Tang Dynasty to Du Fu's mature hand in the prosperous Tang Dynasty. His prosodic pattern requires that the number of words in the poem should be uniform.
There are eight taboos in writing rhyming poems: first, avoid loneliness; The second is to avoid the tail; The third is to avoid the tail; The third is to avoid tone sandhi; The fourth is to avoid losing stickiness; The fifth is to avoid palms; Sixth, avoid repeating words; The seventh is to avoid straightforwardness; Eight is to avoid misusing old and new rhymes.
In a word, the so-called Gu Ping has only one word in life except the last rhyme, that is, throwing herself at the poet is a taboo. For example, the third word is tone, except for the seventh rhyme, only the fourth word is tone, which is a lonely tone. Lonely and plain sentences are limited to rhyming sentences. In other words, the last word is a flat sentence (that is, a rhyming sentence). Be careful not to be lonely and boring. A blank sentence is not a lonely flat sentence, even if there is only one flat sentence.
Therefore, when the ancients were writing metrical poems, we can easily explain and know the reason why the last sentence should converge.