public void addSimplePairFeatures(int pidx, int aidx, ArrayList<String> feats) {
   String predForm = sent.getWord(pidx);
   String argForm = sent.getWord(aidx);
   Set<String> a = sig.getSimpleUnkFeatures(predForm, pidx, cs.prm.language);
   for (String c : a) {
     feats.add(c);
   }
   Set<String> b = sig.getSimpleUnkFeatures(argForm, aidx, cs.prm.language);
   for (String c : b) {
     feats.add(c);
   }
 }
 // ---------- Meg's "Simple" features. ----------
 public void addSimpleSoloFeatures(int idx, ArrayList<String> feats) {
   String wordForm = sent.getWord(idx);
   Set<String> a = sig.getSimpleUnkFeatures(wordForm, idx, cs.prm.language);
   for (String c : a) {
     feats.add(c);
   }
 }