Basic explanation: Harmony is echo. In traditional poetics, harmony poems consist of more than two poems, the first is the original song, and the second is the echo poem. Different genres have different requirements for the use and rhythm arrangement of flat tones. Pay attention to rhyme, rhyme, rhyme.
Pinyin rules:
(1) The vowel of seven syllables such as "Zhi, Chi, Shi, Ri, Zi, Nv and Si" is I, that is, the spelling of words such as Zhi, Chi, Ri, Zi, Ci and Si.
(2) Vowel ㄦ is written as er, and when it is used as the ending, it is written as r. For example, "child" spells Ertong, and "flower" spells Hu ι r.
(3) When the vowel ㄝ is used alone, it is written as ㄝ.
(4) When there is no vowel before the vowel in line I, it is written as yi (clothes), yɑ (elegance), ye (yeah), yɑo (waist), you (excellent), yɑn (smoke), ying (cause) and yɑng (middle).
When there is no vowel before the vowel in line U, it is written as wu (Wu), w\u (Frog), wo (Wo), w\u I (Oblique), wei (Wei), w\u n (Bend), wen (Wen), w\u ng (Wang) and Wen (Wang).
The vowels in line ü, when there is no initial in front, are written as yu (pedantic), yu (about), yuɑn (unjust) and yun (dizzy). ④ Omit the above two points.
When vowels in line ü are spelled with initials J, Q and X, they are written as ju (ju), qu (Qu), xu (Xu), Ju (Sense), que (Absence) and Xue (Xue), and the above two points are also omitted; But when spelled with the initials L and N, it is still written as lü (Lu), lüe (abbreviation), nü (female) and nüe (abuse).
(5) The initial letter 5) When 5)iou, uei and uen are added together, they are written as iu, ui and un, such as niu, gui and lun.