Judging from the rhyme of this couplet, the suffixes "Fu" and "Xiang" are both flat, so they can't be judged by flat. Judging from causality. First of all, the first part is to welcome spring, blessings and weddings, and the second part is to accept blessings, good luck and peace.
The characteristics of couplets are:
Words should be equivalent, parts of speech should be equivalent, structure should be commensurate, rhythm should correspond, balance should be harmonious, and content should be relevant.
Couplets are one of the traditional cultures in China and the treasure of traditional culture in China. The antithesis of couplets must be regular and balanced.