<td class="tag">
    <a href="/tag/android"  rel="tag">
         <img src="http://127.0.0.1/idf2.png" >
    android
    </a>          
</td>
编码:
soup = BeautifulSoup(html)
print html.td.a.string   # output None
BeautifulSoup4 中的哪个方法可以检索<a>的内容android