—  No._____ is old.

对于平面直角坐标系内的任意两点A（x₁,y₁),B(x₂,y₂)，定义它们之间的一种“距离”：||AB||=|x₁-x₂|+|y₁-y₂|．给出下列三个命题：
①若点C在线段AB上，则||AC||+||CB||=||AB||;
②在$△ABC$中，若∠C=90°，则||AC||²+||CB||²=||AB||²；
③在$△ABC$中，||AC||+||CB||>||AB||．
其中真命题的个数为(   )

根据句意及首字母提示完成短文

    My grandfather died in 2005 at the age of 78.He was b____ in 1927.When he was twenty—nine,he m ____     to Guangzhou,the capital of Guangdong Province.There he first worked in a factory and then in a food company.In 1952,he m____a girl from Hunan Province.They had five daughters and my mother is their s____ daughter.

    When my grandfather was young,he didn't have a bicycle,so he usually____ to work every day.In his free time he liked to l____to music on the radio, b____ he didn't have a TV at that time.He also liked to p____chess with his friends.When he was sixty,he started w ____plays.One of his plays was successful. Many people still see this play and  e____it.