-- some open lexicon N_Pl ::= "sons" ; N ::= "son" ; N ::= "wine" ; N2 ::= "plan" ; N3 ::= "value" ; PN ::= "John" ; A ::= "intelligent" ; A2 ::= "devoted" ; AV ::= "tedious" ; AV ::= "difficult" ; AS ::= "marvellous" ; AQ ::= "independent" ; V0 ::= "rain" | "rains" ; V ::= "sleeps" | "sleep" ; V2 ::= "loves" | "love" ; V3 ::= "sends" | "send" ; VV ::= "wants" | "want" ; Adv ::= "here" ; AdA ::= "very" ; AdV ::= "always" ; -- a bigger lexicon N ::= "car" | "house" | "flight" | "aircraft" ; N_Pl ::= "cars" | "houses" | "flights" | "aircraft" ; PN ::= "Boston" | "New" "York" | "Baltimore" ;