12. The system of claim 11 , wherein generating the plurality of candidate query rewrites further comprises concatenating the search query with each prior search query of the plurality of search queries.
12. The system of claim 11 , wherein generating the plurality of candidate query rewrites further comprises concatenating the search query with each prior search query of the plurality of search queries. 13. The system of claim 12 , wherein each prior search query includes a timestamp, and wherein scoring the candidate query rewrites includes weighting candidate rewrites based, in part, on the age of the corresponding prior query.