When reading, because the word "pian" at the back is the fourth sound (piàn), the word "one" should be changed to the second sound (yí). That is to say, it should be pronounced as (yí piàn piàn).

The tone sandhi law of "one";

1, "one" is pronounced as an ascending tone (second sound) before the tone is removed. Be consistent, be consistent, be consistent, be consistent, be consistent.

2. Before the tone adjustment (first tone), tone adjustment (second tone) and rising tone (third tone), the word "one" is changed to falling tone (fourth tone). For example, a family spends a lot of money every day and every year. ...

3. Read softly between monosyllabic overlapping verbs. Think, talk, listen and try. ...