php正则提取数据,该怎么解决

<br>$str='<br>        <br>                <br>                    <span><br>                        <span><br>                            表演者:<br>                                    Various Artists<br>                        </span><br>                    </span><br>                    <br>                    <br><br>                <br>                    <br>    <span>版本特性:</span> Clean<br>    <br><br><br>                <br>                    <br>    <span>介质:</span> Audio CD<br>    <br><br><br>                <br>                    <br>    <span>发行时间:</span> 2012-12-18<br>    <br><br><br>                <br>                    <span><br>                        <span><br>                            出版者:<br>                                    Universal Republic<br>                        </span><br>                    </span><br>                    <br>                    <br><br>                <div class="clear">
                 
              
              
        
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