“Underwent” is the past simple form of the verb “undergo”, and it’s the one that you’d default to when talking about something that you underwent. It would normally be used to tal… See more

“Undergone” is what is known as the “past participle” form of the verb. It’s not exactly a straightforward verb tense, because you can’t use it all on your own. You need an auxiliary ve… See more

According to the Google Ngram Viewer, “undergone” is more popular than “underwent” by a very small margin. The information showcases the fact that since the year 19… See more

You should use “had undergone” and avoid using “had underwent”, as the former is grammatically correct and the latter is awkward and incorrect. “Undergone” is the past partici… See more