（1） 有一个主持人控制开关和8路抢答按扭，当主持人允许抢答时才能进行抢答操作，并用一个数码管显示抢答选手的号码，同时其他选手不能再抢答。 （2）电路上...

代码说明：

（1） 有一个主持人控制开关和8路抢答按扭，当主持人允许抢答时才能进行抢答操作，并用一个数码管显示抢答选手的号码，同时其他选手不能再抢答。 （2）电路上要加个蜂鸣器的电路，当有选手抢答时蜂鸣器响一下。 （3）要有倒计时功能，开始抢答时开始倒20秒计时，用两个数码管显示，当有人抢答时停止倒计时。 2.2拓展部分 用按键可设置倒计时的时间，范围在5秒到30秒之间。-(1) has a host switch and 8-way control button to answer in, when the moderator allowed to be carried out to answer in time to answer in operation, and use an LED display to answer in the number of players, while other players can no longer answer in his place. (2) the circuit, we should add a buzzer circuit, when there are players when the buzzer rang to answer in about. (3) to have the countdown feature to begin to answer in 20 seconds when you start down time, using two digital tube display, when someone stops to answer in the countdown. 2.2 The expansion of part of the buttons can be set with the countdown time, the range of 5 seconds to 30 seconds.