OK, got it!

# get pages for each city, keyword, proxy 
    
    for my $city (@cities) {
        my $keyword = shift @keywords;
        my $proxy   = shift @proxies;
        
     
        print "City :    [$city]\nKeyword: [$keyword]\n";

          print "Current proxy:$proxy)\n";

          # Use this UA/Proxy to fetch something....
          $ua->proxy(['http'], 'http://'.$proxy);     
          my $url = join '',$link1 . $city ."+". $keyword,
                            $link2 . $city ."+". $keyword,
                            $link3;
          my $response = $ua->get($url);
          print "getting $url\n";      
          if ($response->is_success) {
            my $filename = "Bing/${city}_${keyword}.html";
            print "Creating $filename\n";
            open my $fh, ">", $filename 
                 or die("Could not open $filename. $!");
            print $fh $response->decoded_content;  # or whatever
            close $fh;
          } else {
            die $response->status_line;
          }
          print "\n"; 
        }
    close($fh);
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