document.write ("<b>上一篇</b>：<a href='/DocHtml/699/2015/4/1/2535443934677.html'>春秋五霸与战国七雄</a><br><b>下一篇</b>：<a href='/DocHtml/699/2014/6/14/5398481034673.html'>怎样学习和研究化学</a>")