相关疑难解决方法(0)

我知道这是简单的PHP逻辑,但它不会起作用......

 $str = "dan";
 if(($str != "joe") 
   || ($str != "danielle")
   || ($str != "heather")
   || ($str != "laurie")
   || ($str != "dan")){         

 echo "<a href='/about/".$str.".php'>Get to know ".get_the_author_meta('first_name')." &rarr;</a>";
                  }

我究竟做错了什么？