who's knocking at the door
who knock at the door
pro:rel part prep det:art n
who's knocking at the door ?
h uː z WORD_BOUNDARY n ɒ k ɪ ŋ WORD_BOUNDARY a t WORD_BOUNDARY ð ə WORD_BOUNDARY d ɔː WORD_BOUNDARY
w h o ' s WORD_BOUNDARY k n o c k i n g WORD_BOUNDARY a t WORD_BOUNDARY t h e WORD_BOUNDARY d o o r WORD_BOUNDARY