A.
B.
C.
D.
答案:D
He always gets when giving a speech.
A. nervous B. nervously C. relaxed
设有关系R(A,B,C,D,E),各属性函数依赖集合有F{A→B,B→C,C→D,C→E},若把关系R分解为R1(A,B,C)和R2(C,D.E),则R1属于第【 】范式。