在计算机中采用二进制，是因为()
A.可降低硬件成本
B.两个状态的系统具有稳定性
C.二进制的运算法则简单
D.上述三个原因
参考答案：D
She bought the same skirt at a lower price at the same shop where I bought mine because she was a __________ customer.
A．common
B．regular
C．normal
D．usual
