NullReferenceException：对象引用未设置为对象_的实例

Question

代码：

    if (StoneScript.scoreTex.text != "Pickaxe")
    {
        if(GrassScript.amount >= 3)
        {
            GrassScript.amount = GrassScript.amount - 3;
            GrassScript.scoreText.text = "Wood: " + GrassScript.amount;
            StoneScript.scoreTex.text = "Pickaxe";
        }
    }

它可以更早地工作，但现在不会。

在StoneScript.cs中：

public static Text scoreText;
public static Text scoreTex;
public static int amount = 0;