为什么这段代码不会在浏览器中提示一次？

Question

我正在为一个叫做“构建测验”的树屋挑战。我必须提出问题，根据用户的回答，我应该显示哪些问题他/她是否对错。我现在特别苦恼的是理解为什么下面的JavaScript代码不会至少支持我的一个问题。 任何有识之士将不胜感激。

// Questions 
var questions = [ 
      ['Who is the President of the U.S?', 'Donald Trump'], 
      ['Who is the Vice President of the U.S?', 'Mike Pence'], 
      ['Who won the Super Bowl last year?', 'Patriots'] 
]; 

//Variables go here, answer, response, question ect 
var correctAnswers = 0; 
var question; 
var answer; 
var response; 
var html; 

function print(message) { 
    document.write(message); 
} 

    //below is how you loop the questions above 
for (var i = 0; i < questions.length; i += 1); { 
    question = questions[i][0]; 
    answer = questions[i][1]; 
    response = window.prompt(question); 
    if (response === answer) { 
     correctAnswers += 1; 
    } 
} 

html = "you got" + correctAnswers + "question(s) right."; 
print(html); 

Answer 1

循环表达式的右括号与代码块的开始大括号之间的“for”循环中有一个分号分号。