I don't know what happened
I do know what happen
pro:sub mod v pro:int v
i don't know what happened ?
aɪ WORD_BOUNDARY d oʊ n t WORD_BOUNDARY n oʊ WORD_BOUNDARY w ʌ t WORD_BOUNDARY h æ p ə n d WORD_BOUNDARY
i WORD_BOUNDARY d o n ' t WORD_BOUNDARY k n o w WORD_BOUNDARY w h a t WORD_BOUNDARY h a p p e n e d WORD_BOUNDARY