static Triple<S> splitAtThirdPersonVerb(S s) {
  L<S> tok = nlTok(s);
  int i = indexOfAny(allToLower(tok), thirdPersonVerbs());
  if (i < 0) null;
  ret triple(
    trimJoinSubList(tok, 0, i),
    tok.get(i),
    trimJoinSubList(tok, i+1));
}