I didn't know how to do it
I do know how to do it
pro:sub mod v pro:int inf v pro:per
i didn't know how to do it.
aɪ WORD_BOUNDARY d ɪ d n tʰ WORD_BOUNDARY n əʊ WORD_BOUNDARY h aʊ WORD_BOUNDARY tʰ ə WORD_BOUNDARY d uː WORD_BOUNDARY ɪ tʰ WORD_BOUNDARY
i WORD_BOUNDARY d i d n ' t WORD_BOUNDARY k n o w WORD_BOUNDARY h o w WORD_BOUNDARY t o WORD_BOUNDARY d o WORD_BOUNDARY i t . WORD_BOUNDARY