ion() {
          this.currentIndex++;
          this.selectedAnswers = [];
          this.result = null;

          if (this.currentIndex < this.questions.length) {
            this.currentQuestion = this.questions[this.currentIndex];
          } else {
            this.currentQuestion = null;
            this.quizOver = true;
          }
        },
        clearCache() {
          const ok = confirm("清除所有做题记录吗？")
          if (ok) {
            localStorage.clear()
            location