sub sequential {
  my $self    = shift;
  my $sl_ctl  = $self->{slctl};
  my $sl_len  = scalar(@$sl_ctl);
  my $mode    = $self->{params}->{mode};
  my $m_clust = $mt_param{$mode}->{cluster};
  my @tl_rtl  = ();

  &log("mt: entering sequential, mode >$mode<...\n");

  $m_clust = &get_maxval([1, $m_clust]);

  for(my $i = 0; $i < $sl_len; $i++) {
    my $idx_la = &get_minval([$sl_len-1,
                     $i + $m_clust]);
    my $phrase;
    my $rawtr;
  retry:

    &log("I: $i IDX_LA: $idx_la\n");

    $phrase = join ' ', @$sl_ctl[$i..$idx_la];
    $rawtr  = $self->get_rawtr($phrase);
    if(@$rawtr) {
      my $disam = $self->disambiguate($phrase,
                        $rawtr,
                        $i,$idx_la);
      push @tl_rtl, $disam;
    } else {
      if($idx_la > $i) {
      $idx_la--;
      goto retry;
      }
      push @tl_rtl, $phrase;
    }
    $i = $idx_la;
  }

  @tl_rtl = &trim(@tl_rtl);
  $self->{tlrtl} = \@tl_rtl;

  return TRUE;
}