Sleep(3000);  //暂停3000ms
    
    keybd_event('A', 0, 0, 0);//按下a键
     //参数1:虚拟键码
    //参数2：定义该键的硬件扫描码
    //参数3：KEYEVENTF_KEYUP：若指定该值，该键将被释放；若未指定该值，该键将被按下

    keybd_event('A', 0, KEYEVENTF_KEYUP, 0);//松开a键


    //按组合键  shift+a
    keybd_event(16, 0, 0, 0);//按下Shift键
    keybd_event('A', 0, 0, 0);//按下a键
    keybd_event('A', 0, KEYEVENTF_KEYUP, 0);//松开a键
    keybd_event(16, 0, KEYEVENTF_KEYUP, 0);//松开Shift键