the first time 和at the first time和for the first time的区别

the first time 第一次,是名词,在句子中只能做名词的成分.
at the first time 是介词短语,是“在第一次”
for the first time 也是第一次,是个副词短语,在句子中做状语.
例子：
He won the match at the first time.
他在第一次比赛中就获胜了.
We should inform the insurance agent at the first time.
我们应在第一时间通知保险公司代理.
For the first time I felt repentance and sorrow.
我第一次感到后悔,感到难过.