php替換中文字符

$words = ["我", "你", "他", "她"];//過濾庫
$sentence = "我和你一起去他家找她";//待過濾的句子
foreach($words as $word)//遍歷過濾庫的詞
{
$len = strlen($word);//獲取過濾詞的長度
$pos = strpos($sentence,$word);//尋找過濾詞的位置
$sentence = substr_replace($sentence,'', $pos, $len); 
}
echo $sentence;