PHP – 获取文本的前两句话？

我的变量$content包含我的文本.我想从$content创建一个摘录并显示第一个句子,如果句子短于15个字符,我想显示第二个句子.

我已经尝试从文件中删除前50个字符,它可以工作：

<?PHP echo substr($content,50); ?>

但我对结果不满意(我不希望任何词语被削减).

是否有PHP函数获取整个单词/句子,而不仅仅是substr？

非常感谢！

我想通了,但它很简单：

<?PHP
    $content = "My name is Luka. I live on the second floor. I live upstairs from you. Yes I think you've seen me before. ";
    $dot = ".";

    $position = stripos ($content,$dot); //find first dot position

    if($position) { //if there's a dot in our soruce text do
        $offset = $position + 1; //prepare offset
        $position2 = stripos ($content,$dot,$offset); //find second dot using offset
        $first_two = substr($content,$position2); //put two first sentences under $first_two

        echo $first_two . '.'; //add a dot
    }

    else {  //if there are no dots
        //do nothing
    }
?>