对于这样一个非常简单的XML:
<catalog>
    <cd>
        <title>Empire Burlesque</title>
        <artist>Bob Dylan</artist>
        <country>USA</country>
        <company>Columbia</company>
        <price>10.90</price>
        <year>1985</year>
    </cd>
    <cd>
        <title>Hide your heart</title>
        <artist>Bonnie Tyler</artist>
        <country>UK</country>
        <company>CBS Records</company>
        <price>9.90</price>
        <year>1988</year>
    </cd>
    <cd>
        <title>Greatest Hits</title>
        <artist>Dolly Parton</artist>
        <country>USA</country>
        <company>RCA</company>
        <price>9.90</price>
        <year>1982</year>
    </cd>
</catalog>
和一个简单的xslt:
<xsl:template match="/">
 <xsl:apply-templates/>  
</xsl:template>
为什么会产生如下输出:
Empire Burlesque
Bob Dylan
USA
Columbia
10.90
1985
Hide your heart
Bonnie Tyler
UK
CBS Records
9.90
1988
Greatest Hits
Dolly Parton
USA
RCA
9.90
1982
所有XML标签都去了哪里?我应该<xsl:apply-templates/>用<xsl:copy>标签包围以 
 使其工作吗?