前提：(“x)(P(x)Þ(Q(x)∧R(x)))，($x)(P(x)∧S(x))结论：(“x)(R(x)∧S(x));前提：(“x)(G(x)ÞH(x))，~($x)(F(x)∧H(x))结论：($x)F(x)Þ($x)G(x)