For this boundary position, the 6-gram including the three words before and the three words after the boundary is included as a feature; additionally, all n-grams for n < 6 such that either w i or w i+1 (or both) is in the n-gram are included as features.
all n-grams in a six word window of boundary position i are included as features, except those that include neither w i nor w i+1 in the n-gram.