As in the following examples. Note that the CP-CLF is attached at the IP-level, and that the pronoun "það" is tagged "PRO-N" rather than "ES".
( (IP-MAT-SPE (CONJ og-og) (NP-SBJ (PRO-N það-það)) (HVPI hefur-hafa) (ADVP (ADV líklega-líklega)) (VBN verið-vera) (NP-PRD (PRO-N ég-ég)) (, ,-,) (CP-CLF-SPE (WNP-1 0) (C sem-sem) (IP-SUB-SPE (NP-OB1 *T*-1) (NP-SBJ (PRO-N þú-þú)) (VBDI sást-sjá))) (. ;-;)) (ID 1850.PILTUR.NAR-FIC,.237))
( (IP-MAT-SPE (" ") (NP-SBJ (PRO-N Það-það)) (BEPI er-vera) (NP-PRD (NP (NS-N dýr-dýr)) (CONJP (CONJ og-og) (NP (ADJ-N óþörf-óþarfur) (N-N ást-ást)))) (, ,-,) (CP-CLF-SPE (WNP-1 0) (C sem-sem) (IP-SUB-SPE (NP-SBJ *T*-1) (RP um$-um) (VBPI $breytir-breyta) (NP-OB1 (N-D skóla$-skóli) (D-D $num-hinn)) (PP (P í-í) (NP (N-A hesthús-hesthús))))) (. .-.)))
Sometimes the complement of "það" in the cleft is not nominative, but rather the case that matches the gap inside of the CP-CLF. The case marking of this argument seems to be optional in modern Icelandic. These cases are annotated the same way as above, with the NP-PRD exceptionally appearing in a non-nominative case, as in the example below:
( (IP-MAT-1 (NP-SBJ (PRO-N Það)) (BEPI er) (NEG ekki) (NP-PRD (NPRS-A gyðinga) (FP-A einasta)) (, ,-,) (IP-MAT-PRN=1 (ADVP (ADVR heldur)) (NP-PRD (Q-A alla) (D-A þá) (PP (P af) (NP (Q-D öllum) (NS-D þjóðum))))) (, ,-,) (CP-CLF (WNP-2 0) (C sem) (IP-SUB (NP-OB1 *T*-2) (NP-SBJ (NP-POS (PRO-N þinn)) (N-N faðir)) (HVPI hefur) (NP-OB2 (PRO-D þér)) (VBN gefið))) (. .-.)))