I don't know why
I do know why
pro:sub mod v pro:rel
i don't know why.
aɪ WORD_BOUNDARY d əʊ n tʰ WORD_BOUNDARY n əʊ WORD_BOUNDARY w aɪ WORD_BOUNDARY
i WORD_BOUNDARY d o n ' t WORD_BOUNDARY k n o w WORD_BOUNDARY w h y . WORD_BOUNDARY