在一个关系二维表中，主属性是指（ ）
A．非主码
B．候选码
C．主码
D．非候选码
参考答案：B
25. It is only after my father was long gone _____ understand his deep love for me.
A．I could
B．could I
C．that I could
D．when I could
戴思恭是怎样论述痰的生成及其病变和治疗大法的
