#!/usr/bin/env perl

use strict;
use warnings;

my @del_words = qw{is an to for from};
my $del_words_alt = join q{|} => @del_words;
my $del_re = qr{\b(?>$del_words_alt)\b\s*};

while (<>) {
    s{$del_re}{}g;
    print;
}