Query answering over OWLs and RDFs on the Semantic Web is, in general, a deductive process. To this end, OWL, a family of web ontology languages based on description logic, has been proposed as the language for the Semantic Web. However, reasoning even on ALC, a description logic weaker than OWL, faces efficiency problem. To obviate this problem, at least for ALC, we propose a partition approach that improves the efficiency by splitting the search space into independent Aboxes. Each partition class, i.e., an Abox, can be queried independently. The answer to a query is the simple combination of the answers from each Abox. We prove the correctness of this approach and we outline how to represent compactly the content of each independent Abox. This work can be seen as an optimization for querying a deductive semistructured database.