// e.g. i -> am? -> a bot
static S ai_answerIsQuestion(T3<S> t) {
  if (!eqicOneOf(t.b, "am?", "are?", "is?")) null;
  
  // find out what t.a is
  L<S> is_l = ai_superclasses(t.a, dropQuestionMark(t.b));
  printStruct(+is_l);
  
  // find out what t.c is
  L<S> askedFor_l = ai_superclasses(t.c);
  printStruct(+askedFor_l);
  
  for (S askedFor : askedFor_l)
    for (S is : is_l)
      if (has(is, "is not", askedFor))
        ret "No - " + is + " is not " + askedFor;
  
  null;
}