Understanding the Past Tense of “Undergo”: Forms, Usage, and Examples

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The verb “undergo” is a commonly used irregular verb in English, frequently appearing in academic writing, professional communication, and everyday conversations. Whether describing medical procedures, corporate changes, or personal experiences, mastering the correct past tense form—“underwent”—is essential for clear and accurate communication.

Because “undergo” is irregular, it does not follow the typical “-ed” pattern for past tense verbs, which can lead to confusion and mistakes among learners. Understanding its past forms, appropriate contexts, and grammatical structures will help you avoid errors and express yourself confidently.

This comprehensive guide benefits English language learners, exam candidates, teachers creating lesson plans, professionals drafting reports, and anyone seeking to improve their grammar skills. Here, you will find definitions, conjugation tables, usage rules, detailed examples, common mistakes with corrections, advanced insights, and practice exercises—all designed to ensure thorough understanding and mastery.

Table of Contents

3. Definition Section

3.1. What Does “Undergo” Mean?

The verb undergo means to experience or be subjected to something, often something unpleasant, challenging, or involving a change.

Examples:

  • She had to undergo surgery after her accident.
  • The company will undergo major restructuring next year.
  • He underwent rigorous training before the competition.

3.2. Grammatical Classification

Part of speech: Verb

Verb type: Irregular verb

Verb group: Transitive verb (requires an object)

Base form: undergo

3.3. Past Tense of “Undergo”

The simple past tense of “undergo” is “underwent”, which is irregular and does not end with “-ed”. The past participle form is “undergone”.

Base Form Simple Past Past Participle Present Participle
undergo underwent undergone undergoing

3.4. Function and Usage Contexts

“Underwent” is used to describe a process or experience that was completed in the past. It emphasizes that the action is finished.

Common contexts:

  • Medical: She underwent surgery last year.
  • Business: The company underwent restructuring.
  • Training or exams: He underwent rigorous training.

Distinguish this from the present perfect (“has undergone”), which connects the experience to the present:

  • She has undergone surgery (experience relevant now).
  • She underwent surgery (action finished in the past).

4. Structural Breakdown

4.1. Verb Forms of “Undergo”

Below is a comprehensive conjugation table of “undergo” across common tenses:

Tense Form Example
Simple Present I/You/We/They undergo
He/She/It undergoes		 She undergoes treatment every month.
Present Continuous am/is/are undergoing They are undergoing tests now.
Simple Past underwent He underwent surgery last year.
Past Continuous was/were undergoing She was undergoing treatment when I visited.
Present Perfect has/have undergone They have undergone changes recently.
Past Perfect had undergone He had undergone several tests before surgery.
Future will undergo She will undergo treatment next week.

4.2. Forming the Simple Past Tense

The simple past of “undergo” is the irregular form underwent. Unlike regular verbs, it does not end in -ed. Instead, it changes internally from go to went within the word.

Example: undergo → underwent (similar to go → went)

4.3. Sentence Structure with “Underwent”

Here’s how to use “underwent” in affirmative, negative, and question forms:

Form Structure Example
Affirmative Subject + underwent + object The student underwent an interview.
Negative Subject + did not + base form “undergo” + object The student did not undergo an interview.
Question Did + subject + base form “undergo” + object? Did the student undergo an interview?

4.4. Tense Contrast

Understanding the difference between past simple, present perfect, and past continuous helps convey the correct meaning.

Tense Example Meaning
Past Simple
(finished past event)		 She underwent treatment last year. Completed action in the past with no connection to now.
Present Perfect
(past event with result now)		 She has undergone treatment. Past action relevant to the present.
Past Continuous
(ongoing past action)		 She was undergoing treatment when I arrived. Action was in progress at a specific past moment.

5. Types or Categories

5.1. Simple Past Tense Usage

Use underwent to describe:

  • Single completed action:
    She underwent surgery.
  • Sequential past events:
    First, he underwent training, then he joined the team.

5.2. Past Perfect Tense with “Undergone”

Use had undergone to show an experience completed before another past event.

Example:

  • She had undergone surgery before she moved abroad.
  • By 2019, the company had undergone several changes.

Timeline illustration:

[Earlier past] had undergone → [Later past] moved abroad

5.3. Passive Voice Constructions

Although rare, “undergo” can appear in passive voice, especially in perfect tenses.

Examples:

  • The procedure was undergone by many patients.
  • The changes have been undergone by the team.

Transformation:

  • Active: The patient underwent the surgery.
  • Passive: The surgery was undergone by the patient.

5.4. Continuous Forms (Past Continuous and Perfect Continuous)

Past Continuous:

  • She was undergoing treatment when I visited. (action in progress at a past time)

Past Perfect Continuous:

  • He had been undergoing therapy for months before he improved. (ongoing action up to a point in the past)

6. Examples Section

6.1. Basic Examples of “Underwent” in Sentences

  • She underwent surgery last year.
  • The building underwent repairs recently.
  • He underwent a medical examination.
  • The car underwent a complete overhaul.
  • They underwent training before deployment.
  • The bridge underwent a safety inspection.
  • The team underwent rigorous testing.
  • The law underwent several amendments.
  • The software underwent an update.
  • The country underwent economic reform.

6.2. Complex Sentence Examples

  • After the athlete underwent knee surgery, she returned stronger than ever.
  • The company underwent multiple audits before receiving certification.
  • Once he underwent background checks, he was granted access to the facility.
  • The bridge underwent extensive maintenance to improve its safety.
  • Following the scandal, the organization underwent major restructuring efforts.
  • The city underwent rapid development over the past decade.
  • After she underwent therapy, her condition improved significantly.
  • Before publishing, the manuscript underwent several rounds of editing.
  • Before launch, the spacecraft underwent rigorous testing procedures.
  • Once the treaty underwent ratification, it became binding.

6.3. Examples by Context

Medical:

  • She underwent chemotherapy last year.
  • He underwent a heart transplant.
  • The patient underwent a series of tests.
  • My father underwent knee replacement surgery.

Education:

  • All candidates underwent an interview process.
  • The students underwent a comprehensive exam.
  • She underwent a challenging training program.

Business:

  • The company underwent a merger last year.
  • The department underwent reorganization.
  • The product underwent quality testing before release.

Personal experiences:

  • He underwent a difficult period after losing his job.
  • She underwent a major transformation in her life.
  • They underwent significant hardships during the journey.

6.4. Comparison Examples: Different Tenses

Tense Example
Past Simple The city underwent many changes.
Present Perfect The city has undergone many changes.
Past Continuous The city was undergoing many changes during that period.

6.5. Positive, Negative, and Interrogative Examples

Affirmative Negative Question
She underwent surgery. She did not undergo surgery. Did she undergo surgery?
They underwent training. They didn’t undergo training. Did they undergo training?
The project underwent revisions. The project did not undergo revisions. Did the project undergo revisions?

7. Usage Rules

7.1. When to Use “Underwent”

  • For actions or experiences fully completed in the past.
  • When specifying a definite past time: last year, yesterday, in 2019.
  • With past time markers: She underwent training in March.

7.2. When NOT to Use “Underwent”

  • Do not use with present time markers like today, now, or currently.
  • Avoid in continuous tenses; instead, use was undergoing or is undergoing.

7.3. Irregular Verb Considerations

  • “Underwent” is irregular—do not add -ed.
  • Never use “undergoed” as a past tense form.
  • Use “underwent” only for the simple past tense.

7.4. Common Exceptions and Special Cases

  • Negatives and questions use the base form “undergo” with did not or did:
    • She did not undergo surgery.
    • Did she undergo surgery?
  • In perfect tenses, use “undergone” with has/have/had:
    • She has undergone surgery.
    • He had undergone training before the test.
  • She might have undergone surgery.
  • He could have undergone training abroad.
  • They should have undergone more tests.

7.6. Summary Table: When to Use Each Form

Tense/Construction Correct Form Example
Simple Past underwent She underwent surgery.
Negative Past did not undergo She did not undergo surgery.
Present Perfect has/have undergone She has undergone surgery.
Past Perfect had undergone She had undergone surgery.

8. Common Mistakes

8.1. Incorrect Past Form: “Undergoed”

  • ❌ She undergoed surgery.
  • ✅ She underwent surgery.

8.2. Using “Underwent” in Questions or Negatives

  • ❌ Did she underwent surgery?
  • ✅ Did she undergo surgery?

8.3. Confusing “Underwent” with “Undergone”

  • ❌ She has underwent surgery.
  • ✅ She has undergone surgery.

8.4. Using Present Form for Past Events

  • ❌ Yesterday, he undergo surgery.
  • ✅ Yesterday, he underwent surgery.

8.5. Incorrect Continuous Forms

  • ❌ She was underwent surgery.
  • ✅ She was undergoing surgery.

8.6. Table of Common Errors and Corrections

Incorrect Sentence Correct Sentence
She undergoed a test last week. She underwent a test last week.
Did he underwent an operation? Did he undergo an operation?
He has underwent many challenges. He has undergone many challenges.
They was underwent training. They were undergoing training.

9. Practice Exercises

Answers with explanations follow each exercise.

9.1. Fill-in-the-Blank Exercises

  1. Last year, the city __________ major changes.
  2. She __________ surgery in 2018.
  3. They did not __________ any training.
  4. The software has __________ multiple updates.

Answers:

  1. underwent (simple past for a completed action in the past)
  2. underwent (simple past with a specific time reference)
  3. undergo (base form after “did not”)
  4. undergone (past participle with present perfect “has”)

9.2. Correction Exercises

Identify and correct the mistakes:

  1. He has underwent a background check.
  2. Did you underwent surgery?
  3. She undergoed a difficult process.

Answers:

  1. He has undergone a background check.
  2. Did you undergo surgery?
  3. She underwent a difficult process.

9.3. Sentence Construction

Use “underwent” to write sentences about:

  • A medical procedure: My mother underwent heart surgery last month.
  • A company change: The startup underwent rapid expansion last year.
  • An education experience: All applicants underwent a thorough interview process.

9.4. Identification Exercises

Identify if the sentence is correct (Yes/No):

  1. The machine underwent maintenance. — Yes
  2. They did not underwent tests. — No (Correct: did not undergo tests)
  3. He had undergone training. — Yes

9.5. Multiple Choice Questions

  1. She (underwent / undergoed) an operation last year.
  2. They (has undergone / have underwent) many changes.

Answers:

  1. underwent
  2. have undergone

10. Advanced Topics

10.1. Nuances of “Underwent” vs. “Undergone”

“Underwent” is used for completed events in the past with no relation to the present.

“Undergone” is a past participle used with perfect tenses, emphasizing the relevance or result now or a sequence of past events.

Example:

  • She underwent surgery last year. (completed event)
  • She has undergone surgery. (experience relevant now)

10.2. Stylistic Choice and Formality

“Underwent” and “undergone” are formal and precise, often used in academic or professional contexts. In casual speech, alternatives may be preferred:

  • Experienced: She experienced surgery (less common, but possible)
  • Went through: She went through surgery
  • Was subjected to: He was subjected to tests

10.3. Idiomatic Usage and Collocations

Common collocations with “underwent”:

Collocation Example
underwent surgery She underwent surgery last week.
underwent testing The car underwent testing before launch.
underwent changes The city underwent changes over time.
underwent treatment He underwent treatment for cancer.
underwent evaluation The plan underwent evaluation by experts.

10.4. Passive Constructions and Emphasis

Using passive voice shifts focus from the subject experiencing the process to the process itself.

  • Active: Many patients underwent the procedure.
  • Passive: The procedure was undergone by many patients.

Note: Passive with “undergo” is rare and more common in technical or legal writing.

10.5. Academic and Technical Usage

In research, “underwent” and “undergone” are used precisely to describe participant experiences or experimental procedures.

  • Participants underwent a cognitive assessment.
  • The material has undergone several tests to ensure quality.

11. FAQ Section

  1. What is the past tense of “undergo”?
    The simple past tense is “underwent.”
  2. Is “underwent” regular or irregular?
    It is an irregular verb; it does not end with -ed.
  3. What is the past participle of “undergo”?
    The past participle is “undergone.”
  4. Can I say “undergoed”?
    No, “undergoed” is incorrect. The correct past tense is “underwent.”
  5. When do I use “underwent” instead of “undergone”?
    Use “underwent” for the simple past. Use “undergone” with perfect tenses (has/have/had undergone).
  6. How do I form questions with “underwent”?
    Use did + subject + undergo: Did she undergo surgery?
  7. What’s the difference between “underwent” and “was undergoing”?
    “Underwent” = finished past event.
    “Was undergoing” = ongoing past action at a certain time.
  8. Can “underwent” be used in the passive voice?
    No, but “undergone” can be used in passive constructions (e.g., The procedure was undergone by many patients).
  9. Is “underwent” formal or informal?
    It is more formal, common in academic and professional writing.
  10. How do I use “underwent” in negative sentences?
    Use did not + undergo: She did not undergo treatment.
  11. What are common mistakes with “underwent”?
    Using “undergoed”, using “underwent” in questions or negatives (should be “undergo”), confusing with “undergone.”
  12. What synonyms can I use instead of “underwent”?
    Experienced, went through, was subjected to, faced, endured.

12. Conclusion

To communicate effectively, it is essential to understand that the past tense of “undergo” is “underwent”, an irregular form used to describe finished experiences or processes. Its past participle, “undergone,” is used in perfect tenses and passive voice.

Remember the key differences:

  • Underwent = simple past (She underwent treatment.)
  • Undergone = past participle (She has undergone treatment.)

Be mindful of common mistakes such as “undergoed,” incorrect negations, or confusing verb forms. Use the many examples, tables, and exercises provided here to reinforce your understanding.

Practicing these structures will help you express yourself more accurately and confidently in English, whether in conversation, writing, or professional settings. Mastery of irregular verbs like “undergo” is a significant step toward fluent, precise English communication.

Keep practicing, reviewing, and applying this knowledge to achieve your language goals!

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