能够实现“收回用户U4对学生表(STUD)中学号(XH)的修改权”的SQL语句是()。
参考答案:REVOKE UPDATE(XH) ON STUD FROM U4
One advantage of G3 mobiles is that it has become a very useful tool for________daily communication. [ ]
A. taking on
B. speeding up
C. working on
D. making up
油压机是借助油作为()的介质,通过()介质进入柱塞缸,推动柱塞加压工作。