遍历JSON元素并获取其值时出错

我有一个JSON文件,比方说,像这样的东西。。。

{
    ...{
     },
    "notifications": {
        "satisfactory_record":"satisfactory record",
        "invalid_token" : "Invalid Token",
        ...
    },
    "faq": {
        "title" : "Frequently asked questions",
        "questions": [
            {
                "title" : "What is...?",
                "content" : "This is..."
            },
            {
                "title" : "What is...?",
                "content" : "This is..."
            },
            {
                "title" : "What is...?",
                "content" : "This is..."
            },
            ...
        ]
    }
}

好吧,我想拿这个东西 "faq" "questions" 第页的标题和内容 faq.php

<?php

echo "<ul>";

$json = json_decode(file_get_contents('file.json'), true); // Array
$questions = $json['faq']['questions'];

foreach($questions as $question){

    echo "<li>";
    echo "<span>$question['title']</span>";
    echo "<p>$question['content']</p>";
    echo "</li>";
}

echo "</ul>";

?>

但它不起作用,因为它抛出了以下错误: Warning: Invalid argument supplied for foreach()

这就是我想要的结果:

注意:我使用的是关联数组而不是集体约定的对象,请不要告诉我将JSON转换为对象而不是数组。