Thanks ! Now boole prover in my file is :
boole :-
get_wff(_A,_L).
get_wff(A,L) :-
read_term(A, [variable_names(N)]),
time(judge(A,L)),
(
last(L,1) -> write('to prove that the formula is a tautology:'),nl,
write(N),nl,
write(L)
;
last(L,0) -> write('to prove that the formula is not a tautology:'),nl,
write(N),nl,
write(L)
).
It provides clear output.