let totalScore = 0;
            let remainingQuestions = questionsAndAnswers.slice(); // 初めは全ての問題が残っている

            function displayRandomQuestion() {
                if (remainingQuestions.length === 0) {
                    document.getElementById('question').textContent = '全ての問題を解き終わりました！';
                    return;
                }

                const randomIndex = Math.floor(Math.random() * remainingQuestions.length);
                const questionObj = remainingQuestions[randomIndex];
                const question = questionObj.question;

                document.getElementById('question').textContent = question;
                document.getElementById('userAnswer').value = '';
                document.getElementById('answerResult').textContent = '';
            }

            function checkAnswer() {
                const userAnswer = document.getElementById('userAnswer').value.toLowerCase().trim();
                const currentQuestion = document.getElementById('question').textContent;
                const questionObj = remainingQuestions.find(qa => qa.question === currentQuestion);

                const correctAnswer = questionObj.answer.toLowerCase();
                const answerResultElement = document.getElementById('answerResult');

                document.getElementById('totalScore').textContent = `合計点数: ${totalScore}/12点`;

                remainingQuestions = remainingQuestions.filter(qa => qa.question !== currentQuestion); // 解答した問題を取り除く
                displayRandomQuestion();
            }