The two synchronous grammars were created by applying different pre-processing to the parallel treebank.
for the HPSG→PTB-CFG direction, 1) the PTB-CFG trees in the parallel treebank were binarized in such a way that maximized the number of commonspan node pairs; 2 2) commas in the PTB-CFG trees were raised as high as possible, approximating the change of the position of commas by the Mayz program; 3) the POS tags for 'not' are changed from 'RB' to 'RB-not,' because in PTB, 'not' is treated differently from other adverbs; 4) base NPs in PTB-CFG trees are marked as 'NP-B.'