带有使能端的4输入数据选择器，S0, S1, S2, C0, C1为输入，C1，C2为使能输入，P, Q, R, T为输出，c1c2=00时输出全为0，c1c2=01时输出全为1，c1c2=10时数据选择，c1c2=11时输出是c1c2=10时的反。-4 with Enable input data selector, S0, S1, S2, C0, C1 as input, C1, C2 an enable input, P, Q, R, T as an output, c1c2 = 00 a