1. A phrase pair collecting apparatus for collecting hypotheses of phrase pairs based on one or more seed pairs each consisting of first and second phrases representing a cause and a result, respectively, each of said phrase pairs consisting of two phrases assumed to represent causality, each of said first and second phrases including a combination of a noun and a predicate template; said apparatus comprising: a storage medium configured to: store said one or more seed pairs; store semantic relation patterns each representing a semantic relation pattern between words; store word pairs each related to any of the stored semantic relation patterns; a processor configured to: determine a semantic relation pattern that matches a noun pair consisting of the nouns in said first and second phrases in each stored seed pair, wherein the determined semantic relation pattern is related to at least one of the stored word pairs; and generate a new hypothesis by replacing a noun pair of a given seed pair of the one or more seed pairs with each of the stored word pairs related to the semantic relation pattern determined to be matching said noun pair; wherein the generation of the new hypothesis improves information extraction from electronically available documents.
2. The phrase pair collecting apparatus according to claim 1 , wherein: the storage medium is further configured to store predicate templates expressing mutually contradictory meanings; and for each of the first and second phrases for each of said one or more seed pairs, the processor is further configured to generate a new hypothesis by replacing the predicate template with another predicate template contradictory to the predicate template, wherein the another predicate template is read from said storage medium.