static S ai_verbPhraseFromThirdPerson(S s) {
  L<S> tok = javaTok(s);
  for (int i = 1; i < l(tok); i += 2)
    if (endsWithIC(tok.get(i), "s")) {
      tok.set(i, dropLast(tok.get(i)));
      break;
    }
  ret join(tok);
}