说明：  时序电路——抢答器，K1、K2、K3、K4各控制一个按钮，DJ代表主持人，在抢答开始前，DJ先按一下按钮，然后在开始比赛，K1—K4中任意按下按钮后，其他钮按下均无效，重新比赛时，DJ需要再按一下按钮。抢答结果用LED显示。
(Sequential Circuits- Answer devices, K1, K2, K3, K4 the control of a button, DJ on behalf of the host before the start of the Answer, DJ press the button, and then at the beginning of competition, K1-K4 in the arbitrary press the button and press the other buttons are invalid, re-match, DJ need to then click the button. Answer the result of using LED display.)