e+eh e+eh e+eh
e eh e eh e eh .
e WORD_BOUNDARY  ɛ h WORD_BOUNDARY e WORD_BOUNDARY  ɛ h WORD_BOUNDARY e WORD_BOUNDARY  ɛ h WORD_BOUNDARY
e WORD_BOUNDARY e h WORD_BOUNDARY e WORD_BOUNDARY e h WORD_BOUNDARY e WORD_BOUNDARY e h WORD_BOUNDARY