第一次按下时，显示“D1”；第二次按下时，显示“D1D2”；第三按下时，显示“D1D2D3”，8个全显示完毕，再按下按键下时，给出“嘀”提示音。- When the first press shows "D1" the second time when the press shows that "D1D2" the third press, the show "D1D2D3", 8 full-show finished, and t