9. A corpus expansion method, comprising: collecting corpus using sample seeds by a corpus expansion apparatus; generating new sample seeds by the corpus expansion apparatus, based on the sample seeds having been used and the collected corpora; determining, by a processor, a corpus expansion strategy based on all the sample seeds having been used and the new sample seeds; refining the new sample seeds based on the corpus expansion strategy; and repeating the above steps until a predefined condition is reached; wherein said corpus expansion strategy includes at least one of the information about the class in specific field in which the sample seeds need to be expanded and the information about which sample seed needs to be deleted in said new sample seeds, wherein said refining step refines the new sample seeds based on at least one of the information about the class in specific field in which the sample seeds need to be expanded and the information about which sample seed needs to be deleted in said new sample seeds.
9. A corpus expansion method, comprising: collecting corpus using sample seeds by a corpus expansion apparatus; generating new sample seeds by the corpus expansion apparatus, based on the sample seeds having been used and the collected corpora; determining, by a processor, a corpus expansion strategy based on all the sample seeds having been used and the new sample seeds; refining the new sample seeds based on the corpus expansion strategy; and repeating the above steps until a predefined condition is reached; wherein said corpus expansion strategy includes at least one of the information about the class in specific field in which the sample seeds need to be expanded and the information about which sample seed needs to be deleted in said new sample seeds, wherein said refining step refines the new sample seeds based on at least one of the information about the class in specific field in which the sample seeds need to be expanded and the information about which sample seed needs to be deleted in said new sample seeds. 11. The corpus expansion method according to claim 9 , wherein, the step of generating new sample seeds comprises at least one of generating new sample seeds based on linguistic structure features and generating new sample seeds based on known seed annotator.