On the tone 3 of neighboring modified tone in a polysyllable in phonetics-teaching

Tone 3 of neighboring modified tone in a polysyllable is a vague belt in phonetics teaching.Most textbooks deal with this problem very simply like this: first divide the polysyllable into two or three syllables,and then make tone 3 according to the phonemic-changing rule of neighboring modified tone in these two or three syllables.However,this method is not very convincing.Starting from the special situations of tone 3 of neighboring modified tone of three syllables,based on the syntactic structures and rhyme theory,the author of this thesis aims to put forward the principle of the tone 3 of neighboring modified tone in a polysyllable.