but I'm not sure
but I not sure
conj pro:sub neg adj
but i'm not sure .
b ʌ t WORD_BOUNDARY aɪ m WORD_BOUNDARY n ɑː t WORD_BOUNDARY ʃ ʊ ɹ WORD_BOUNDARY
b u t WORD_BOUNDARY i ' m WORD_BOUNDARY n o t WORD_BOUNDARY s u r e WORD_BOUNDARY