Mode: "#default"

      <xsl:stylesheet
                  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                  version="2.0">
            <xsl:output  method="xml"
                        indent="yes"
                        omit-xml-declaration="yes"/>

            <xsl:template  match="/aaa">
                  <xsl:apply-templates  select="bbb"/>
                  <xsl:apply-templates  select="bbb"
                              mode="#default"/>
                  <xsl:apply-templates  select="bbb"
                              mode="m1"/>
                  <xsl:apply-templates  select="ccc"
                              mode="#default"/>
            </xsl:template>

            <xsl:template  match="bbb"
                        mode="#default">
                  <default-BBB/>
            </xsl:template>

            <xsl:template  match="bbb"
                        mode="m1">
                  <mode-BBB/>
            </xsl:template>

            <xsl:template  match="ccc">
                  <default-CCC/>
            </xsl:template>

      </xsl:stylesheet>

      <aaa>
            <bbb/>
            <ccc/>
      </aaa>

      <default-BBB/>
      <default-BBB/>
      <mode-BBB/>
      <default-CCC/>