选择题 .  Web SQL is a SQL-like     71    language for extracting information from the web. Its capabilities for performing navigation of web     72    make it a useful tool for automating several web-related tasks that require the systematic processing of either all the links in a     73    , all the pages that can be reached from a given URL through     74    that match a pattern, or a combination of both. Web SQL also provides transparent access to index servers that can be queried via the Common     75    Interface.71.