he did help didn't he
he do help do he
pro:sub v n mod pro:sub
he did help didn't he ?
h iː WORD_BOUNDARY d ɪ d WORD_BOUNDARY h ɛ l p WORD_BOUNDARY d ɪ d n t WORD_BOUNDARY h iː WORD_BOUNDARY
h e WORD_BOUNDARY d i d WORD_BOUNDARY h e l p WORD_BOUNDARY d i d n ' t WORD_BOUNDARY h e WORD_BOUNDARY