我来试着回答一下吧！

个人觉得这个问题I was born＋具体的时间，它的同义句应该是My birthday was 十具体时间。

例如：I was born on May 5th， 2005.

＝My birthday was May 5th， 2005.

如果是be born＋地点，则表示＂出先于某地”，如：

He was born in Shanghai.

＝His birthplace was Shanghai.

希望我的回答能够尽快帮到你啊！