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

Its capabilities for performing navigation of web（）

A．browsers

B．servers

C．hypertexts

D．clients

冯某和朋友齐某一块儿去爬山，在山中的草丛中父现一具尸体，在尸体旁还有一把沾满血迹的菜刀。冯某与齐某有下列哪些义务( )

A．报案

B．保护犯罪现场

C．作证

D．把证据保管好