如何确保测验应用程序中显示正确的答案选择？

我正在开发一个测验应用程序，在其中我有各种各样的问题和答案。答案选择通过与相应问题具有相同的索引与问题相关联（例如，答案数组中的第一个答案选择与问题数组的第一个索引一起使用，依此类推）。但是，我正在从问题数组中随机选择所要提问的问题，因此相应的答案不会随所显示的正确问题一起出现。随机选择和显示的问题中出现正确答案的最佳方法是什么？另外，如何防止已经回答的问题在测验失败并被重置之前不会再次被随机选择？谢谢。

这是我的代码：

import UIKit 

class ViewController:UIViewController {
    //random question generation function
    func randomQuestion() {
        index = Int(arc4random_uniform(UInt32(questions.count)))
        questionLabel.text = questions[index]
    }

    //costants
    let questions = ["Who is Thor's half brother?", "What is the name of Thor's hammer?"]
    var answers = [["Atum", "Loki", "Red Norvell", "Kevin Masterson"], ["Mjolinr", "Uru", "Stormbreaker", "Odin's Staff"]]

    //variables
    var currentQuestion = 0
    var rightAnswerBox:UInt32 = 0
    var index = 0

    //Question Label
    @IBOutlet weak var questionLabel: UILabel!

    //Answer Button
    @IBAction func buttonAction(_ sender: AnyObject) {
        if (sender.tag == Int(rightAnswerBox)) {
            print ("Correct!")
        } else {
            wrongSeg()
            print ("Wrong!")
        }

        if (currentQuestion != questions.count)
        {
            newQuestion()
        }
    }

    override func viewDidAppear(_ animated: Bool)
    {
        newQuestion()
    }

    //function that displays new question
    func newQuestion()
    {
        //countdown timer section
        randomQuestion()

        rightAnswerBox = arc4random_uniform(4)+1

        //create a button
        var button:UIButton = UIButton()

        var x = 1

        for index in 1...4
        {
            //creat a button
            button = view.viewWithTag(index) as! UIButton

            if (index == Int(rightAnswerBox))
            {
                button.setTitle(answers[currentQuestion][0], for: .normal)
            } else {
                button.setTitle(answers[currentQuestion][x], for: .normal)
                x += 1
            }
        }

        currentQuestion += 1
        randomImage()
    }