a badá a badá a badá
a badá a badá a badá .
a WORD_BOUNDARY β a d a WORD_BOUNDARY a WORD_BOUNDARY β a d a WORD_BOUNDARY a WORD_BOUNDARY β a d a WORD_BOUNDARY
a WORD_BOUNDARY b a d á WORD_BOUNDARY a WORD_BOUNDARY b a d á WORD_BOUNDARY a WORD_BOUNDARY b a d á WORD_BOUNDARY . WORD_BOUNDARY