延迟上课的英语是 "delayed start of class"。这个短语的来源是由 "delay"（延迟）和 "start"（开始）两个单词组合而成，表示上课的时间被延迟。
例句：
The teacher has announced that the start of class will be delayed by 30 minutes.
（老师宣布上课时间将被推迟 30 分钟。）
Due to the snowstorm, the start of class has been delayed until tomorrow.
（由于暴风雪，上课时间被推迟到明天。）
The principal has decided to delay the start of class in order to give students more time to prepare for the exams.
（校长决定延迟上课时间，以给学生们更多时间准备考试。）