use strict;
use warnings;

## flag
my $flag = 0;

while(<DATA>){
  my $line = $_;
  if ($flag){
    ## we have already seen the flag, so print the line
    print $line;
  }
  else {
    ## haven't yet seen the flag
    ## so let's see if this line contains it
    
    if ($line =~ m/^Sentence/){
      ## if we do see it, set the flag, 
      ## so we no longer look for it, but just spew out the lines
      $flag = 1;
    }
  }
}