it is not is isn't
it be not be be
pro:per cop neg aux cop
it is not is isn't .
ɪ ɾ WORD_BOUNDARY ɪ z WORD_BOUNDARY n ɑː t WORD_BOUNDARY ɪ z WORD_BOUNDARY ɪ z ə n t WORD_BOUNDARY
i t WORD_BOUNDARY i s WORD_BOUNDARY n o t WORD_BOUNDARY i s WORD_BOUNDARY i s n ' t WORD_BOUNDARY