verb_body = ? all verb bodies, see vocabulary.txt ?;
noun = ? all nouns, see vocabulary.txt ?;
adjective = ? all adjectives, see vocabulary.txt ?;
adverb = ? all adverbs, see vocabulary.txt ?;
preposition = ? all prepositions, see vocabulary.txt ?;
conjunction = ? all conjunctions, see vocabulary.txt ?;
past_verb = verb_body, "a";
present_verb = verb_body, "i";
future_verb = verb_body, "u";
progressive_past_verb = "~", past_verb;
progressive_present_verb = "~", present_verb;
progressive_future_verb = "~", future_verb;