There wouldnt be enough water for us if we didnt _________. A.turn to the oceans for more

A.stuff

B.lassic

C.wouldnt

D.tap

A.wouldnt

B.neednt

C.couldnt

D.mustnt

A.Not at all

B.By no means

C.No, I wouldnt

D.Oh, never

A.只有ENO不能取空值

B.只有CNO不能取空值

C.只有PAY不能取空值

D.ENO与CNO都不能取空值

She wouldnt take a drink, ______ stay for dinner.

A．much more

B．much as

C．still as

D．still less

A.Theyd have to get permission.

B.Jack wouldnt like it,

C.She thinks it might work.

D.Other assistants should be consulted

对于第7题的两个基本表，有一个SQL语句： SELECT ENO, ENAME FROM EMP WHERE DNO NOT IN (SELECT DNO FROM DEPT WHERE DNAME='金工车间');其等价的关系代数表达式是：______。

A．πENO,ENAME(σDNAME≠'金工车间'(EMPDEPT))

B．πENO,ENAME

C．πENO,ENAME(EMP)-πENO,ENAME (σDNAME='金工车间'(EMPDEPT))

D．πENO,ENAME (EMP)-πENO,ENAME (σDNAME≠'金工车间'(EMPDEPT))