13. The method as recited in claim 12 wherein the sentences are grouped in pairs to form sentence pairs.
13. The method as recited in claim 12 wherein the sentences are grouped in pairs to form sentence pairs. 14. The method as recited in claim 13 wherein the filtering is performed by: an identity filter configured to discard any one of the snippet set that does not include the first sentence of the Chinese couplet and a returned second sentence; a neighbor filter configured to pass through the returned second sentence of the sentence pairs not discarded by the identity filter; a length filter configured to discard any one of the returned second sentences passed through by the neighbor filter and that does not have sentence length that corresponds to the first sentence of the Chinese couplet.