# Worker function.
sub process_chunk {
    my ($chunk_ref) = @_;

    $$chunk_ref =~ s/[[:punct:]]//g;
    $$chunk_ref =~ s/[0-9]//g;
    $$chunk_ref =~ s/w(as|ere)/be/gi;
    $$chunk_ref =~ s/ need.* / need /gi;
    $$chunk_ref =~ s/ .*meant.* / mean /gi;
    $$chunk_ref =~ s/ .*work.* / work /gi;
    $$chunk_ref =~ s/ .*read.* / read /gi;
    $$chunk_ref =~ s/ .*allow.* / allow /gi;
    $$chunk_ref =~ s/ .*gave.* / give /gi;
    $$chunk_ref =~ s/ .*bought.* / buy /gi;
    $$chunk_ref =~ s/ .*want.* / want /gi;
    $$chunk_ref =~ s/ .*hear.* / hear /gi;
    $$chunk_ref =~ s/ .*came.* / come /gi;
    $$chunk_ref =~ s/ .*destr.* / destroy /gi;
    $$chunk_ref =~ s/ .*paid.* / pay /gi;
    $$chunk_ref =~ s/ .*selve.* / self /gi;
    $$chunk_ref =~ s/ .*self.* / self /gi;
    $$chunk_ref =~ s/ .*cities.* / city /gi;
    $$chunk_ref =~ s/ .*fight.* / fight /gi;
    $$chunk_ref =~ s/ .*creat.* / create /gi;
    $$chunk_ref =~ s/ .*makin.* / make /gi;
    $$chunk_ref =~ s/ .*includ.* / include /gi;
    $$chunk_ref =~ s/ .*mean.* / mean /gi;
    $$chunk_ref =~ s/ talk.* / talk /gi;
    $$chunk_ref =~ s/ going / go /gi;
    $$chunk_ref =~ s/ getting / get /gi;
    $$chunk_ref =~ s/ start.* / start /gi;
    $$chunk_ref =~ s/ goes / go /gi;
    $$chunk_ref =~ s/ knew / know /gi;
    $$chunk_ref =~ s/ trying / try /gi;
    $$chunk_ref =~ s/ tried / try /gi;
    $$chunk_ref =~ s/ told / tell /gi;
    $$chunk_ref =~ s/ coming / come /gi;
    $$chunk_ref =~ s/ saying / say /gi;
    $$chunk_ref =~ s/ men / man /gi;
    $$chunk_ref =~ s/ women / woman /gi;
    $$chunk_ref =~ s/ took / take /gi;
    $$chunk_ref =~ s/ tak.* / take /gi;
    $$chunk_ref =~ s/ lying / lie /gi;
    $$chunk_ref =~ s/ dying / die /gi;
    $$chunk_ref =~ s/ made /make /gi;
    $$chunk_ref =~ s/ used.* / use /gi;
    $$chunk_ref =~ s/ using.* / use /gi;

    # Output orderly and serially.
    MCE->relay_lock;
    print $OUT_FH $$chunk_ref; $OUT_FH->flush;
    MCE->relay_unlock;
}