RewriteRule不能使用加号(+或*)字符

Asi*_*bal 6 regex apache .htaccess mod-rewrite

RewriteRule ^([a-z]).php$  /index.php?zig=$1 [NC,L] # working
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此规则正常运行.但

RewriteRule ^([a-z]+).php$  /index.php?zig=$1 [NC,L] # not working
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要么

RewriteRule ^([a-z]\+).php$  /index.php?zig=$1 [NC,L] # not working
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不管用.差异是(+).如何+在上面的代码中使用?