在雇员信息表中关系EMP中,( )属性是外键。
A.雇员号
B.雇员名
C.部门号
D.工资
参考答案:A
She doesn’t plan her days. She watches TV ______ evening and changes channels ______ few minutes. So for her this summer just means another boring vocation.
A.in; every
B.every; every
C.every; each
D.every; in
气体分馏装置发生停热源的情况,下列哪项处理是正确的()。
A、装置正常停工
B、装置紧急停工
C、装置维持操作
D、短时间内维持操作,时间长则正常停工