[课堂练习] 2、 现有公式～(x)(y)(z)[(A∨B)∧～C]，在经过减少否定符号的辖域后得到公式为：     A (x)(y)(z)[(～A∧～B)∨～C] B (x)(y)(z)[～(A∨B)∧C] C (x)(y)(z)[～(A∨B)∧C] D (x)(y)(z)[～(A∨B)∧C] E (x)(y)(z)[～(A∨B)∧C]   F (x)(y)(z)[～(A∨B)∧C]   返回课堂