The assignment is to draw the one correct parse tree for each of three sentences, given this grammar: A -> V "@" A | A ":" A | V V -> "a" | "b" | "c" | ... | "z" To deal with ambiguity, use these specifications: ":" has higher precedence than "@" ":" has left associativity Here are the problems: 1) b : a @ c : d 2) a @ b : c @ d : e 3) a : b @ c : d : e