说明：  LED 小灯实验是比较基础的实验之一，上一个“ Hello World！”实验里已经利用到了Arduino 自带的LED，这次我们利用其他I/O 口和外接直插LED 灯来完成这个实验，我们需要的实验器材除了每个实验都必须的Arduino 控制器和USB 下载线以外的
(The LED light experiment is one of the more basic experiments. The last "Hello World! The Arduino LED has been used in the experiment. This time, we used other I/O ports and LED lights plugged in externally to complete the experiment. The experimental equipment we need is not only the Arduino controller and USB download wire that are necessary for each experiment)