键码的定义:在实体集的范围内惟一标识 ______ 。
参考答案:实体
—Jimmy, had a lot of parties recently.
—Yes, that might _____ his failure in the examination.
A.sum up
B.account for
C.push for
D.make sense of
人体的生长发育依赖气的
A.推动作用B.温煦作用C.防御作用D.固摄作用E.气化作用