For instance Zhang and Sun Lee (Zhang and Lee, 2003) reported an accuracy of 90% for English questions, while Li and Roth (Li and Roth, 2002) achieved 98.8% accuracy.
they used a training set of 5,500 questions and a test set of 500 questions, while in our experiments we used for training 405 for each 45 test questions (10-fold-cross-validation).