I will go shopping on Sunday.（Sunday指的是这个星期天）/ I went shoppingon Sunday (Sunday 指的是上一个星期天）
两句都没加the，说明星期有就近指代功能，它伴随动作时间的变化而变化。
那样He died on the Sunday of the car accident.这句为何不能随时间变化而变化,必须要加the呢? 假如如此的话，I went shopping on Sunday atthe end of last month 这句加the吗？
I went shopping on Sunday at the end of last month. 这里Sunday 前不需要the, 由于at the end of last month 一般看作状语。在乎思上=on the last Sunday of last month.