早教吧作业答案频道 -->英语-->
they have known each other for two years的同义句 they( ) ( ) ( ) each other two years ago
题目详情
they have known each other for two years的同义句 they( ) ( ) ( ) each other two years ago
▼优质解答
答案和解析
got to know
看了 they have know...的网友还看了以下：
two week's time还是two weeks' timeI will give you__ 2020-05-16 …
设有关系R(A,B,C)和S(A,D,E,F),若将关系代数表达式:∩R.A,R.B,S.D,S.F 2020-05-23 …
假设有如下两个关系R和S:则以下查询语句:SELECT A,B,C,D,E FROM R,S WHE 2020-05-24 …
假设有如下两个关系R和S:则以下查询语句:SELECT A,B,C,D,E FROM R,S WHE 2020-05-24 …
A.πA,D(σC=D(R×S))B.πA,R,D(σS,C=R,D／(R×S))C.πA,R,D( 2020-05-26 …
A.πA,D(σC=D(R×S))B.πA,R.D(σR.C=S.D(R×S))C.πA,R.D(σ 2020-05-26 …
下列式子中,不正确的是______。A.R－S=R－(R∩S)B.R=(R－S)∪(R∩S)C.R∩ 2020-05-26 …
A.πA,D(σC=D(R×S))B.πA,R.D(σS.C=R.D(R×S))C.πA,R.D(σ 2020-05-26 …
1．请画图说明数据库系统的三级模式结构.2．已知R、S如图所示,求：R∪S,R∩S,R-S,R×S 2020-07-08 …
R={,,},S={,,},请求出R∪S,R∩S,R-S,dom(R),ran(R),dom(R-S 2020-12-31 …