if ( $atail and $ntail ne '' ) {
    ...
    elsif ( !$atail and $ntail ne '' ) {
    ...
    elsif ( not ($atail eq '' and $ntail eq '' )) {

##</code><code>##

    if ( $atail and $ntail ) {
    ...
    elsif ( $atail ) {
    ...
    elsif ( $ntail ) {
    ...

##</code><code>##

    elsif($checkPrefix and 
          $unprefBase and	# Set in an earlier test, above
          $savgrp = &group_of($unprefBase, 1) and # This time, try to derive a group for the base.
          &member($metagroup{$savgrp}, 'NVRB', 'NOUN','VERB','ADJECTIVE','ADVB', 'GERUND')){}

##</code><code>##

    my($sing, $unprefBase, $savgrp, $savbase);