he went down stairs
he go down stair
pro:sub v prep n
he went down stairs ?
h iː WORD_BOUNDARY w ɛ n t WORD_BOUNDARY d aʊ n WORD_BOUNDARY s t ɛ ɹ z WORD_BOUNDARY
h e WORD_BOUNDARY w e n t WORD_BOUNDARY d o w n WORD_BOUNDARY s t a i r s WORD_BOUNDARY