He was made to clean the room a second time.那个second序数词前为什么不加定冠词the 而是a?

题目

He was made to clean the room a second time.那个second序数词前为什么不加定冠词the 而是a?

答案

a second time 再,又的意思 固定用法
如果要用the second time的话,就要It is the second time that he was made to clean the room.这里就成第二次了.