How to find parent

hi,
 
                        <xsl:for-each select=".//fo:block">
                                <ABC>
                                        <xsl:choose>
                                                <xsl:when
test="..=fo:block-container">     ------Something wrong here. I am looking
for the parent of fo:block. If it is fo:block-container then do something,
else do something else
                                                        <!--DO SOMETHING-->
                                                </xsl:when>
                                                <xsl:otherwise>
                                                        <!--DO SOMETHING
ELSE-->                                                 
                                                </xsl:otherwise>
                                        </xsl:choose>
                                </ABC>
                        </xsl:for-each>

Regards 
Manpreet