In our experiments, we found that there were no features where the elimination of each of the features was significantly better than the use of all the features in both Experiments A and B at the  Table 6: Acquired patterns Acquired pattern Notational variant pairs " delete" " " (sio ko syo u/sio ko syo u) (salt and pepper) " (ru) " " " (ha ru ma ge do n/ha a ma ge do n) (Armageddon) " "(ko) " " (hi ki ko mo ri/hi ki ko mo ri) (withdrawal) significance level of 0.05 by a bootstrapping method.
we found that all the features we used in this study were useful and we had better use all the features.