Visual FoxPro参照完整性规则中的更新规则不包括( )
A．“级联”
B．“限制”
C．“忽略”
D．“触发”
参考答案：D
For the common stock of a firm that reported a small loss for the year just ended, the price multiple that is least likely to be meaningful is:（）
A. price to cash flow.
B. leading price to earnings.
C. trailing price to earnings.
有线电视邻频前端系统中的信号接收部分、信号处理部分和信号混合部分的信号输出电平应各自设计调整到多少为好？
