#A
print $a."\n";
#B
require AAAAAA;
#C
eval { require BBBBB; } or do { warn "  cannot load the mobule BBBBB \$^S = $^S\n";
                                print "\ttrying with another module: CCCC\n\n";
                                eval { require CCCC; } or do {warn "cannot load the mobule CCCC \$^S = $^S\n";};
                                if ( $@ ) {warn "no hope with modules today..\n\n";die}
                                else {print "\tsuccesfully loaded CCCC\n" ;}

                                };
#D
eval { 0 } or do { warn "zero is not true \$^S = $^S\n"; };
#E
eval { undef } or die "undef is not enough \$^S = $^S\n";
#F
eval {require AAAAAA;};
if ($@) {
        local $SIG{'__DIE__'} = 'DEFAULT';
        die "default die : $@";
}