单项选择题
A．INSERT B．UPDATE C．DELETE D．SELECT
A．('20080101','cl','90',NUL B．('20080101','c1',90,'成绩优秀') C．('20080101','c1','90','成绩优秀') D．('20080101','c1','79','成绩优秀')
A．INSERT B．ALTER C．UPDATE D．CREATE