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Webster 1913 Edition

imp.

, pret. of undergo. He underwent severe trials.

underwent

simple past tense of undergo
- 1992, Rudolf M. Schuster, The Hepaticae and Anthocerotae of North America: East of the Hundredth Meridian, volume V, page viii
  The repeated exposure, over decades, to most taxa here treated has resulted in repeated modifications of both diagnoses and discussions, as initial ideas of the various taxa underwent—often repeated—conceptual modification.