帮忙写一个XPath
<?xml version="1.0" encoding="ISO-8859-1"?>
<bookstore>
<book>
<title lang="eng">Harry Potter</title>
<author>Mr.A</author>
<author>Mr.B</author>
</book>
<book>
<title lang="eng">Learning XML</title>
<author>Mr.A</author>
<author>Mr.C</author>
</book>
</bookstore>