患者男性,69岁,胰腺癌晚期,病情日趋恶化,患者情绪低落,要求见好友,并急于交代后事,此时患者心理反应处于
A.忧郁期B.愤怒期C.否认期D.协议期E.接受期
参考答案:A
At the foot of the mountain________.
A.a village lie
B.lies a village
C.does a village
D.lying a village
设有关系R=(A,B,C),与SQL语句SELECT DISTINCT A FROM R WHERE B=17等价的关系代数表达式是( )。
A.πA(
B.σB=17(
C.πA(σB=17()
D.σB=17(πA()