they could be but they don't
they could be but they do
pro:sub mod cop conj pro:sub mod
they could be but they don't .
ð eɪ WORD_BOUNDARY k ʊ d WORD_BOUNDARY b iː WORD_BOUNDARY b ʌ t WORD_BOUNDARY ð eɪ WORD_BOUNDARY d oʊ n t WORD_BOUNDARY
t h e y WORD_BOUNDARY c o u l d WORD_BOUNDARY b e WORD_BOUNDARY b u t WORD_BOUNDARY t h e y WORD_BOUNDARY d o n ' t WORD_BOUNDARY