sprintf() [<a href='function.sprintf'>function.sprintf</a>]

错误：Warning: sprintf() [<a href='function.sprintf'>function.sprintf</a>]: Too few arguments inexample.php on line 225。 下面这句不对么？百度没找不到答案

   
   $result = sprintf($newsTpl,$object->FromUserName,$object->ToUserName,time(),count($arr_item));

private function receiveText($object){
    $keyword = trim($object->Content);
    if($keyword=="文本"){
     $content = " this is a text.";
     $result =$this->transmitText($object,$content);
    }
    else if($keyword=="图文"||$keyword=="单图文"){
        $content = array();
        $content[]=array("Title"=>"单图文标题",
                         "Descrption"=>"单图文内容",
                         "PicUrl"=>"http://v1.qzone.cc/pic/201602/12/15/12/56bd85d5cb22d067.jpg%21600x600.jpg",
                         "Url"=>"http://m.cnblogs.com/?u=txw1958");
        $result = $this->transmitNews($object,$content);
    }
    else if($keyword=="多图文"){
        $content = array();
        $content[]=array("Title"=>"多图文标题1",
                         "Descrption"=>"图文内容",
                         "PicUrl"=>"http://v1.qzone.cc/pic/201602/12/15/12/56bd85d5cb22d067.jpg%21600x600.jpg",
                         "Url"=>"http://m.cnblogs.com/?u=txw1958");
        $content[]=array("Title"=>"多图文标题2",
                         "Descrption"=>"图文内容",
                         "PicUrl"=>"http://v1.qzone.cc/pic/201602/12/15/12/56bd85d5cb22d067.jpg%21600x600.jpg",
                         "Url"=>"http://m.cnblogs.com/?u=txw1958");
        $content[]=array("Title"=>"多图文标题3",
                         "Descrption"=>"图文内容",
                         "PicUrl"=>"http://v1.qzone.cc/pic/201602/12/15/12/56bd85d5cb22d067.jpg%21600x600.jpg",
                         "Url"=>"http://m.cnblogs.com/?u=txw1958");
        $result = $this->transmitNews($object,$content);
    }else if($keyword=="音乐"){
        $content = array("Title"=>"七月上",
                         "Descrption"=>"jam",
                         "MusicUrl"=>"http://sc1.111ttt.com/2015/5/12/28/105281351446.mp3",
                         "HQMusicUrl"=>"http://sc1.111ttt.com/2015/5/12/28/105281351446.mp3");
        $result = $this->transmitMusic($object,$content);
    }
    return $result;
}
private function transmitNews($object,$arr_item){
    if(!is_array($arr_item))
        return;
    $itemTpl = "<item>
                <Title><![CDATA[%s]]></Title> 
                <Description><![CDATA[%s]]></Description>
                <PicUrl><![CDATA[%s]]></PicUrl>
                <Url><![CDATA[%s]]></Url>
                </item>";
    $item_str = "";
    foreach($arr_item as $item) {
        $item_str .=sprintf($itemTpl,$item['Title'],$item['Description'],$item['PicUrl'],$item['Url']);
    }
    $newsTpl = "<xml>
                <ToUserName><![CDATA[%s]]></ToUserName>
                <FromUserName><![CDATA[%s]]></FromUserName>
                <CreateTime>%s</CreateTime>
                <MsgType><![CDATA[news]]></MsgType>
                <ArticleCount>%s</ArticleCount>
                <Articles>
                $item_str
                </Articles>
                </xml>";
    $result = sprintf($newsTpl,$object->FromUserName,$object->ToUserName,time(),count($arr_item));
    return $result;
}