未正确显示Array中的问题列表

Question

我用Array在我的项目中提出了一系列问题。以下是我使用的编码。我尝试过3个问题的编码，效果很好。对于我的真实项目，我需要提出20个问题，当一切都完成后，我运行项目，它运行不好。我点击下一步，从Q3开始，它将给Q5，然后Q8，然后跳到Q17。为什么会这样？

stop();
var finalString:String = '';
//var finalString2:String = '';
var _list:Array = ["Q1", "Q2", "Q3,"Q4,"Q5 ","Q6","Q7","Q8 ","Q9","Q10","Q11","Q12", "Q13","Q14", "Q15", "Q16","Q17", "Q18", "Q19", "Q20"];

var _marks:Array = [];
var i:int;
var myscore = 0;
////////////////////////////////////////////

buttonA.buttonMode = true;
buttonB.buttonMode = true;
buttonC.buttonMode = true;
buttonD.buttonMode = true;
skip_btn.buttonMode = true;
score_txt.text = myscore;
question_txt.text = _list[0];

buttonA.label_txt.text = "A. ";
buttonB.label_txt.text = "B. ";
buttonC.label_txt.text = "C. ";
buttonD.label_txt.text = "D. ";
skip_btn.label_txt.text = "SKIP";

buttonA.label_txt.mouseEnabled = buttonB.label_txt.mouseEnabled = buttonC.label_txt.mouseEnabled = buttonD.label_txt.mouseEnabled = skip_btn.label_txt.mouseEnabled = false;

buttonA.addEventListener(MouseEvent.CLICK, q1);
buttonB.addEventListener(MouseEvent.CLICK, q1);
buttonC.addEventListener(MouseEvent.CLICK, q1);
buttonD.addEventListener(MouseEvent.CLICK, q1);
skip_btn.addEventListener(MouseEvent.CLICK, q1);

function q1(event:MouseEvent):void
{
    if(event.currentTarget == buttonA)
    {
        _marks.push("Your answer: ");

    }
    else if(event.currentTarget == buttonB)
    {
        _marks.push("Your answer:");

    }
    else if(event.currentTarget == buttonC)
    {
        _marks.push("Your answer:");
        myscore+=5;

    }
    else if(event.currentTarget == buttonD)
    {
        _marks.push("Your answer:");
    }
    else if(event.currentTarget == skip_btn)
    {
        _marks.push("Skip");
    }

      buttonA.removeEventListener(MouseEvent.CLICK, q1);
      buttonB.removeEventListener(MouseEvent.CLICK, q1);
      buttonC.removeEventListener(MouseEvent.CLICK, q1);
      buttonD.removeEventListener(MouseEvent.CLICK, q1);
      skip_btn.removeEventListener(MouseEvent.CLICK, q1);

    nextFrame();

}