“当我过生日时”用英语怎么说？

如果“过生日”只是指到了生日这一天的话，就是When my birthday comes,如果是指庆祝生日的话，就是When I celebrate my birthday.

When my birthday..... 适用于句首!
.......on my birthday 适用于句尾!

When there is my birthday!

when i birthday

When I celebrate a birthday