RRGparbank

To change a label, click on a node to select a different label from a list. The syntactic category and the function tag (before and after the dash "-") must be selected separately by clicking on the corresponding part of the label.
To add a function tag to a node that does not have one yet, drag it from the list of function tags onto the node.
Re-attach a node by dragging and dropping it on a new parent. This can be used to created discontinuous constituents.
Similarly, nodes can be removed and new ones added by dragging to/from below the tree.
Finally, the bracketing can be edited manually in the text box below the tree; press "validate" to update the tree. Whitespace is ignored. Each token must have a dedicated POS tag.

				[...wait for it...]

(SENTENCE
  (CLAUSE
    (CORE
      (NP (PRO 0=He))
      (OP-MOD 1=could)
      (NUC (V 2=hear))
      (NP
        (CORE_N
          (NUC_Q (ADVP-PERI (CORE_ADV (NUC_ADV (ADV 3=just)))) (QNT 4=enough))
          (PP
            (P 5=of)
            (CLAUSE
              (PrCS (NP-WH (PRO-WH 6=what)))
              (OP-TNS 7=was)
              (CORE
                (NUC (V 8=issuing))
                (PP
                  (CORE_P
                    (NUC_P (P 9=from))
                    (NP (OP-DEF 10=the) (CORE_N (NUC_N (N 11=telescreen))))))))))))
    (CORE (CLM 12=to) (NUC (V 13=realize)))
    (CLAUSE
      (CLM 14=that)
      (CORE
        (NP (PRO 15=it))
        (NP-PERI (PRO 17=all))
        (NUC (V 18=happened))
        (PP-PERI
          (, 19=,)
          (CORE_P
            (NUC_P (P 20=as))
            (CLAUSE (CORE (NP (PRO 21=he)) (NUC (V 23=foreseen))) (OP-TNS 22=had)))))
      (OP-TNS 16=had))
    (. 24=;))
  (CLAUSE
    (CORE
      (NP
        (OP-DEF 25=a)
        (CORE_N
          (AP-PERI (CORE_A (NUC_A (A 26=vast))))
          (AP-PERI (CORE_A (NUC_A (A 27=seaborne))))
          (NUC_N (N 28=armada))))
      (ADVP-PERI (CORE_ADV (NUC_ADV (ADV 30=secretly))))
      (NUC (V 31=assembled))
      (NP
        (OP-DEF 32=a)
        (CORE_N
          (AP-PERI (CORE_A (NUC_A (A 33=sudden))))
          (NUC_N (N 34=blow))
          (PP
            (CORE_P
              (NUC_P (P 35=in))
              (NP
                (NPIP
                  (NP (OP-DEF 36=the) (CORE_N (NUC_N (N 37=enemy))) (POS 38='s)))
                (CORE_N (NUC_N (N 39=rear)))))))))
    (OP-TNS 29=had)
    (CLAUSE-PERI
      (, 40=,)
      (CORE
        (NP
          (OP-DEF 41=the)
          (CORE_N (AP-PERI (CORE_A (NUC_A (A 42=white)))) (NUC_N (N 43=arrow))))
        (NUC (V 44=tearing))
        (PP
          (CORE_P
            (NUC_P (P 45=across))
            (NP
              (OP-DEF 46=the)
              (CORE_N
                (NUC_N (N 47=tail))
                (PP (P 48=of) (NP (OP-DEF 49=the) (CORE_N (NUC_A (A 50=black))))))))))))
  (. 51=.))