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