有四个按钮B1B2B3B4和两个灯泡L1L2的盒子，B1是打开电源的按钮，B4是关闭电源的按钮B2B3是操作按钮B1被按下后为电源打开状态，B4被按下后为电源关闭状态-There are four buttons B1B2B3B4 and two bulbs L1L2 box, B1 is turned on the power button, B4 is shut down the power button B2B3 is B1 is pressed the button operation