单项选择题
Dataitemsareaddedordeletedfromthelistonlyatthetopofthe（）.
A.queue B.stack C.tree D.linearlist
单项选择题 （）meansthataprogramwrittenforonecomputersystemcanbecompiledandrunonanothersystemwithlittleornomodification.
单项选择题 （）hasbecomeafactofmodemlife，withmillionsofpeoplenowshoppingon-line.
单项选择题 Thedata（）includesthefunctionofupdatingdataonadatabase，andretrievingdatafromadatabase.
