sentence1: asahara et al extended hmms so as to incorporate 1 ) position-wise grouping , 2 ) word-level statis-tics , and 3 ) smoothing of word and pos level statistics .
sentence2: asahara et al extended the original hmms by 1 ) position-wise grouping of pos tags , 2 ) word-level statistics , and 3 ) smoothing of word and pos level statistics .