带有 For 循环 PHP 的直通开关案例

请帮忙。

for($i=0; $i<12; $i++ ){
        switch($i) {
            case 0:
            case 1:
            case 2:
            case 3:
            case 4:
                echo ("i is less than 5 <br>");
                break;
            case 5:
            case 6:
            case 7:
            case 8:
            case 9:
                echo ("i is less than 10 <br>");
                break;
            default:
                echo ("i is 10 or more <br>");
        }
    }

这是我在Java书中获得的示例代码，我将上面的代码翻译成PHP。

以下代码的输出：

i is less than 5 
i is less than 5 
i is less than 5 
i is less than 5 
i is less than 5 
i is less than 10 
i is less than 10 
i is less than 10 
i is less than 10 
i is less than 10 
i is 10 or more 
i is 10 or more

我的问题是，为什么情况 0 到案例 3 输出"i 小于 5"，即使它没有任何以下代码并且案例 4 是带有 echo 语句的代码？我很困惑，有人可以向我解释一下。提前谢谢。