下列问题是基于以下叙述：有关系模式R(A,B,C,D) ，F={(A,D) →C,C→B}。
R的所有候选码为______。
A. 候选码为(A,D,C)
B. 候选码为(A，D)
C. 候选码为(A，C)
D. 候选码为(A,D) ，(A,C)
What can we infer from the passage？
A. We should learn what labor-market discrimination is.
B. We should learn to analyze the reasons why there is discrimination in labor markets.
C. We should consider labor-market discrimination from political perspectives.
D. We should learn the size of labor-market discrimination.
Why do women have less job experience on average than men？
A. Because female labor-force participation has increased over the past several decades.
Because women are likely to interrupt their careers to raise children.
C. Because great changes have taken place over the past several decades.
D. Both A and B
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