In a separate window use what you have learned so far to add a second LED to your circuit in Tinkercad. You will need to choose an Arduino pin and connect it the same way you connected the first LED. Make it blink on and off at the same time as the first LED. Hint: you can do this by copying and pasting lines of code in your program; you do not need to write any new code from scratch. The only thing you need to change is the pin number. Try to do this before you look at the slides or video for this section. 
在单独的窗口中，使用您到目前为止学到的知识，在 Tinkercad 中为您的电路添加第二个 LED。您需要选择一个 Arduino 引脚，并以与连接第一个 LED 相同的方式连接它。使其与第一个 LED 同时闪烁。提示：您可以通过在程序中复制和粘贴代码行来实现此目的;您无需从头开始编写任何新代码。您唯一需要更改的是引脚号。在查看本节的幻灯片或视频之前 ，请尝试执行此作。