Table 3 The regular expressions for passives in this research.

From: A corpus-based study of passive voice trajectories in methods sections across three academic branches (1980–2020)

BEa

insertions

-ed

[A-z]+_VBD

nullb

[A-z]+_VVN

[A-z]+_VBP

[A-z]+_RB

[A-z]+_VBZ

[A-z]+_RB [A-z]+_RB

[A-z]+_VBG

[A-z]+_DT

[A-z]+_VBN

[A-z]+_RBR

[A-z]+_VB

[A-z]+_VBG

  1. aThese capital letters are the POS tagged by TreeTagger. VBD = were/was, VBP = are, VBZ = is, VBG = being, VBN = been, VB = be, RB = adverbs, DT = determiners, RBR = comparatives, VVN = past participle. [A-z] means all the words, whether capitalized or not. [A-z]+_VBD can be understood as all the words that are tagged as VBD.
  2. bNull means there are no words between be and past participle.