在关系代数运算中，五种基本运算为
A、并、差、选择、投影、自然连接B
暂无解析
中国自20世纪60年代开始进行海洋油气资源的自营勘探和开发。（）
Happinessdoesn’talways_______money.
Accordingtothe"principles-and-parameters"theory,"principles"refertohighlyabstractpropertiesofgrammarwhichareappliedtolanguageingeneralandwhichgeneratephrasesandatthesametimerestrainthepowerofMovea,while"parameters"allowgeneralprinciplestooperateincertainrestrictedways,accordingtowhichparticulargrammarsofnaturallanguagesvary.
Alinguistictheoryisconstructedaboutwhat______isandhowitworks.
Howmanymonomorphemicwordsarethereinthefollowingwords?catsbossworkimpropertried
