以下Perl程序的输出结果是哪个选项？
$str = "white black or white red";
if ($str =~ /
(?<first>\w+)\s
(?<second>\w+)\s
(?:or|and)\s
\g1\s
(?<third>\w+)
/x){
print "$+{first} $+{second} $+{third}";
}
