What are the similarities and differences between the metrical patterns of poetry bells, metrical poems and couplets?

There are only seven words, and a couplet is always fourteen words. Another difference between Shi Zhong and poetry is that it is not limited to writing a theme, but writing a theme for each sentence. For example, "Wen Tianxiang, Glasses":

It is difficult to save the Southern Song Dynasty;

Make your eyes clear again.

Each cuts the theme, but it is also in harmony with nature and confronts neatly.

Metric poetry is very strict, and there are strict rules on the number, number of words, rhyme, level tone and antithesis of sentences:

1, each song is limited to eight sentences: the five laws stipulate that each sentence is five words, and the whole song is ***40 words; The seven laws stipulate that each sentence has seven words and the whole sentence has fifty-six words.

2, limited to the use of flat rhyme, and a rhyme to the end, the middle can not change rhyme. The five laws take the first sentence as a positive example and rhyme as an example; The seven laws take the rhyme of the first sentence as a positive example, and the non-rhyme as a variant.

3. The sentence pattern and word level of each sentence are stipulated: pay attention to adhesion and rightness.

4. antithesis should be used in each sentence, which is an important feature of metrical poetry. The other two groups don't need to go to war.

Couplets are called "couplets", commonly known as pairs. Concise and profound, neat and balanced, word for word, is a unique art form of Chinese language.