static double ai_regexpMixScoreIC(Collection<S> regexps1, Collection<S> regexps2, Collection<S> sentences) {
  double score = 0;
  for (S s : sentences)
    int score1 = l(matchingRegexpsIC(regexps1, s));
    continue if score1 == 0;
    LS l = matchingRegexpsIC(regexp2, s);
    if (nempty(l)) print(quote(answer) + " because " + s + ": " + l);
    score += score1*l(l);
  }
  ret score;
}