R [A, B, C, D, E, F, G, H]
{E, F} - & gt; {D, G, H}
{G, H} - & gt; {C}

In the relationship between R, according to the existing two FDs, can launch key {A, B, E, F},

But as A result of A, B, C is to draw the underline for the key, so there are other FDs is not listed,

How to judge the relationship paradigm level?