sentence: I remember , when I celebrated my 15th birthday , only one schoolmate wanted to come to my party . I think that that day was one of the worst days of my life .
modified: I remember when I celebreted my 15th birthday , only one schoolmate wanted to come to my party ; I think that this day was one of the worst day of my life .
transformation: PUNCT, SPELL, PUNCT, DET, NOUN:NUM