设有关系R(S，D，M)，其函数依赖集F＝S→D，D→M。则关系R至多满_爱下问搜题

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问题单项选择题

设有关系R(S，D，M)，其函数依赖集F＝S→D，D→M。则关系R至多满足( )。

A．1NF

B．2NF

C．3NF

D．BCNF

答案

参考答案：B

选择题

---You seemed to be impressed by his skill.

---No. It was his courage ________ his skill that really impressed me.

A．but also

B．as well as

C．except for

D．rather than

单项选择题

清洁级以上实验动物的饮水须达到（）的要求。

A.普通生活饮用水

B.无菌

C.软化水

D.纯净水