Old and ex can express the same idea, or not?<br/><br/>We say: This is my <b>old</b> school<br/><br/>or<br/><br/>This is my<b> ex</b> school?<br/><br/>My <b>ex </b>girlfriend is standing over there<br/><br/>or<br/><br/>My <b>old</b> girlfriend is standing over there<br/><br/>?