but they don't know what happened
but they do know what happen
conj pro:sub mod v pro:int v
but they don't know what happened .
b ʌ t WORD_BOUNDARY ð eɪ WORD_BOUNDARY d oʊ n t WORD_BOUNDARY n oʊ WORD_BOUNDARY w ʌ t WORD_BOUNDARY h æ p ə n d WORD_BOUNDARY
b u t WORD_BOUNDARY t h e y WORD_BOUNDARY d o n ' t WORD_BOUNDARY k n o w WORD_BOUNDARY w h a t WORD_BOUNDARY h a p p e n e d WORD_BOUNDARY