In presentational constructions involving the verb ser ('be'), an expletive null subject is usually added to the annotation. If the overt NP agrees with the verb, the NP is co-indexed with the expletive subject: 

( (IP-MAT (NP-SBJ-1 *exp*)
	  (SR-P-3S é)
	  (NP-1 (D-UM-F uma) (N vida) (ADJ-F estúpida))
	  (. .))
  (CORDIAL-SIN; ID VPA15,17))

( (IP-MAT (NP-SBJ-1 *exp*)
	  (SR-P-3S É)
	  (NP-1 (D-F a) (ADJ-F mesma) (N coisa))
	  (. .))
  (CORDIAL-SIN; ID VPA23,9))

( (IP-MAT (NP-SBJ-1 *exp*)
	  (SR-P-3S é)
	  (NP-1 (NPR Fevereiro))
	  (, ,))
  (CORDIAL-SIN; ID CTL48,17))

( (IP-MAT (NP-SBJ-1 *exp*)
	  (SR-P-3S É)
	  (NP-1 (N dia)
		(PP (P de)
		    (NP (NPR São_João)))))
  (CORDIAL-SIN; ID STA26,14))

( (IP-MAT (NP-SBJ-1 *exp*)
	  (SR-D Era)
	  (NP-1 (D-F a)
		(ADJ-F quarta)
		(NPR Dominga)
		(PP (P d@)
		    (NP (D @o) (NPR Advento))))
	  (. :))
  (TYCHO BRAHE; ID B_001_PSD,71.565))

( (IP-MAT (NP-SBJ-1 *exp*)
	  (SR-D Era)
	  (NP-1 (D-UM-F uma)
		(N época)
		(PP (P de)
		    (NP (ADJ mau) (N agouro))))
	  (. !))
  (TYCHO BRAHE; ID A_003_PSD,53.788))

( (IP-MAT (NP-SBJ-1 *exp*)
	  (SR-P-3P São)
	  (NP-1 (N-P nuvens))
	  (. :))
  (CORDIAL-SIN; ID AAL69,2))

( (IP-MAT (NP-SBJ-1 *exp*)
	  (SR-P-3P são)
	  (NP-1 (NUM sete)
		(N-P semanas)
		(PP (P de)
		    (NP (N quaresma))))
	  (, ,))
  (CORDIAL-SIN; ID PVC29,26))

( (IP-MAT (NP-SBJ-1 *exp*)
	  (SR-D-3P Eram)
	  (NP-1 (D-P os) (N-P bailes))
	  (. .))
  (CORDIAL-SIN; ID CTL08,29))

( (IP-MAT (NP-SBJ-1 *exp*)
	  (SR-D-3P Eram)
	  (NP-1 (NUM nove) (N-P irmãos)))
  (CORDIAL-SIN; ID MIN15,41))

( (IP-MAT (NP-SBJ-1 *exp*)
	  (SR-D-3P Eram)
	  (NP-1 (NUM seis)
		(N-P horas)
		(PP (P @de)
		    (NP (D-F @a) (N manhã))))
	  (, ,))
  (CORDIAL-SIN; ID EXB20,7))

( (IP-MAT (NP-SBJ-1 *exp*)
	  (SR-D Foram)
	  (NP-1 (D-P os)
		(ADJ-P últimos)
		(N-P adeuses)
		(PP (P a)
		    (NP (D-F a)
			(N capital)
			(PP (P de)
			    (NP (D-UM um)
				(N país)
				(CP-REL (CP-REL (WPP-2 (P a)
						       (NP (WPRO que)))
						(IP-SUB (PP *T*-2)
							(NP-SBJ *pro*)
							(TR-D tinha)
							(VB-PP prestado)
							(NP-ACC (ADJ-R-P tantos) (N-P serviços))))
					(CONJP (CONJ e)
					       (CP-REL (WNP-3 (WPRO que))
						       (IP-SUB (NP-SBJ *T*-3)
							       (NP-DAT (CL lhe))
							       (VB-D demonstrava)
							       (NP-ACC (D o)
								       (PRO$ seu)
								       (N reconhecimento)
								       (CONJP (CONJ e)
									      (NX (N simpatia)))))))))))))
	  (. .))
  (TYCHO BRAHE; ID A_003_PSD,125.1966))

If the NP and ser do not agree, then the NP is annotated as NP-ACC without co-indexation.

( (IP-MAT (NP-SBJ *exp*)
	  (SR-D-3S era)
	  (NP-ACC (NUMP (NUM um) (, ,) (NUM dois) (, ,) (NUM três))
		  (N-P 'sáveles'))
	  (, ,))
  (CORDIAL-SIN; ID VPA38,80))

( (IP-MAT (NP-SBJ *exp*)
	  (SR-P-3S É)
	  (NP-ACC (N-P fezes))
	  (. .))
  (CORDIAL-SIN; ID PAL25,22))

( (IP-MAT (NP-SBJ *exp*)
	  (SR-D-3S Era)
	  (NP-ACC (NUM sete)
		  (N-P embarcações)
		  (PP (P a)
		      (NP (N-P remos))))
	  (. .))
  (CORDIAL-SIN; ID CLC28,70)) 

( (IP-MAT (NP-SBJ *exp*)
	  (SR-D-3S Foi)
	  (NP-ACC (N-P nervos))
	  (. .))
  (CORDIAL-SIN; ID MST14,30))

( (IP-MAT (NP-SBJ *exp*)
	  (SR-P-3S É)
	  (NP-ACC (N-P ditados)
		  (CP-REL (WNP-1 (WPRO que))
			  (IP-SUB (NP-SBJ-2 *T*-1)
				  (NP-SE-2 (CL se))
				  (VB-P-3P dizem))))
	  (. .))
  (CORDIAL-SIN; ID LVR23,44))

The same principles apply to ser in cleft constructions:

(CP-EXL   (IP-IND   (NP-SBJ-1 *exp*)
                    (SR-D-3S Foi)
                    (NP-1 (PRO ela))
                    (ADV também)
                    (CP-CLF   (WNP-2 0)
                              (C que)
                              (IP-SUB   (NP-SBJ *T*-2)
                                        (VB-D-3S preparou)
                                        (NP-ACC (Q tudo)))))
          (. !))
(CORDIAL-SIN; ID VPA24)

[...]
(IP-SUB (NP-SBJ *exp*-3)
	(NEG não)
	(SR-P-3P são)
	(NP-3 (D-F-P as) (N-P águas))
	(CP-CLF (WNP-2 0)
	        (C que)
		(IP-SUB (NP-SBJ *T*-2)
			(NP-DAT (CL me))
			(VB-P-3P fazem)
			(NP-ACC (N terror))
			(PP (P para)
			    (IP-INF (ADVP (ADV mal))
				    (VB obrar))))))))
[...]
(POST SCRIPTUM; ID CARDS1123,.4)

( (IP-MAT (CONJ Mas)
	  (NP-SBJ *exp*)
	  (ADVP (ADV quase) (ADV sempre))
	  (SR-D-3S era)
	  (NP-ACC (D-F-P as) (N-P raparigas))
	  (CP-CLF (WNP-1 0)
		  (C que)
		  (IP-SUB (NP-SBJ *T*-1)
			  (VB-D-3P trabalhavam)
			  (PP (P @em)
			      (NP (DEM @isso)))))
	  (. .)))

(CORDIAL-SIN; ID MIG03)

Notice that short answers involving presentational ser never include expletive subjects, since no empty categories are codified inside IP-ANS.

E como é que se chamam aquelas tábuas muito fininhas que depois se põem aqui para pôr as telhas em cima?

( (IP-ANS (SR-P-3S É)
          (NP (D o)
              (N forro))
          (. .))
  (CORDIAL-SIN; ID AAL88,11))

Então o que é que ia para o, para o pisão?

( (IP-ANS (SR-D-3S Era)
          (NP  (D-F-P as)
                (N-P mantas)
               (PP  (P de)
                    (NP  (N lã))))
          (. .))
  (CORDIAL-SIN; ID PFT04,7))