first line switch

例句：

1. 1. The first line switch on the TV is very easy to use.
   电视的第一行开关很容易使用。
2. 2. The first line switch in this car is located in the center console.
   这辆车的第一行开关位于中控台。
3. 3. When you turn on the first line switch, the lights will come on automatically.
   当你打开第一行开关时，灯光会自动亮起。