a brrrrr brr ee brrr
a brrrrr brr ee brrr .
a WORD_BOUNDARY b r r r r r WORD_BOUNDARY b r r WORD_BOUNDARY e e WORD_BOUNDARY b r r r WORD_BOUNDARY
a WORD_BOUNDARY b r r r r r WORD_BOUNDARY b r r WORD_BOUNDARY e e WORD_BOUNDARY b r r r WORD_BOUNDARY . WORD_BOUNDARY