5. The system of claim 4 , wherein the one or more hardware processors is further configured to read instructions from the non-transitory memory to cause the system to perform operations comprising: identifying a first sub-tree corresponding to the first needs expression and a plurality of sub-trees corresponding to each of the plurality of needs expressions.
5. The system of claim 4 , wherein the one or more hardware processors is further configured to read instructions from the non-transitory memory to cause the system to perform operations comprising: identifying a first sub-tree corresponding to the first needs expression and a plurality of sub-trees corresponding to each of the plurality of needs expressions. 7. The system of claim 5 , wherein the one or more hardware processor is further configured to read instructions from the non-transitory memory to cause the system to perform operations comprising: determining a matching topicality group corresponding to the user needs expression; determining matching sub-trees by generalizing the user syntactic parse tree to the first sub-tree and each of the plurality of sub-trees in the matching topicality group; and displaying contents corresponding to the matching sub-trees.