设计一个十字路口的交通灯控制电路，要求东西方向车道和南北方向车道两条交叉道路上的车辆交替运行，每次通行时间都设为45秒。时间可设置修改。-Design a crossroads of traffic lights control circuit requires lane east-west direction and north-south direction of the two-lane cross-road vehicles to run alternately, each openin