17. The non-transitory computer readable storage medium of claim 12 , wherein determining the co-occurrence measure for the first input sentence comprises: grouping second input sentences that are determined to be similar to each other; grouping, from the identified pairs of first and second input sentences that include a second input sentence belonging to the group of second input sentences, first input sentences that are determined to be similar to each other; and determining that a cardinality of the group of first input sentences meets a threshold cardinality.
17. The non-transitory computer readable storage medium of claim 12 , wherein determining the co-occurrence measure for the first input sentence comprises: grouping second input sentences that are determined to be similar to each other; grouping, from the identified pairs of first and second input sentences that include a second input sentence belonging to the group of second input sentences, first input sentences that are determined to be similar to each other; and determining that a cardinality of the group of first input sentences meets a threshold cardinality. 19. The non-transitory computer readable storage medium of claim 17 , wherein grouping second input sentences that are determined to be similar to each other comprises grouping second input sentences that are successfully parsed rules associated with the first action.