-What are those?
-They are __________.[ ]
A. pear
B. boxs
C. boat
D. birds
答案:D
设有关系模式S(A,B,C,D) ,则SQL语句“SELECT A,C FROM S”能够完成的关系运算是选择和()
当汇入账户处于()状态时,汇款无法入账。
A.账户已清户
B.账户已没收
C.账户已挂失
D.账户已止付