(3) a. amendment of regulation ⇔ amending regulation b. amendment of X ⇔ amending X c. amendment of documents ⇔ amending documents Using that method, they were able to expand the seed lexicon by a large multiple (15 to 40 times), and the new paraphrase pairs were of reasonably good quality.
they introduced variables only for identical word forms shared by both sides of each pair and left corresponding pairs of lexical variants, e.g., ("amendment", "amending") in (3a), untouched.