ACT® · English: Usage Conventions
Past Tense and Past Participle of Irregular Verbs
Irregular verbs have a plain past form and a separate past participle form, and only a helper verb like have, had, was or were unlocks the participle. No helper means you use the simple past.
Regular verbs just add -ed for past and past participle, so you never notice two forms fighting for the same job. Irregular verbs refuse that shortcut. Drink becomes drank in the simple past and drunk in the past participle, and each form has exactly one use. The simple past stands alone as the main verb: 'He drank the coffee.' The past participle never stands alone; it needs a helper verb like have, has, had, was, or were sitting in front of it: 'He has drunk the coffee.' That pairing is the whole rule.
To apply it fast, scan the sentence for a helper verb near the blank. See 'have,' 'has,' or 'had'? You need the participle: risen, sunk, shaken, drunk, broken. See no helper, just a bare blank doing the main verb's job? You need the simple past: rose, sank, shook, drank, broke. 'The river had risen' works because 'had' is right there. 'The boat sank' works with nothing in front of it; 'the boat sunk' fails because sunk always wants a helper it doesn't have.
This rule sits right next to subject-verb agreement and other usage checks because all of them ask the same question: does this exact word fit this exact slot? Once you've confirmed the verb form matches its helper, you're doing the same kind of precision check you'd do for pronoun case or word choice elsewhere in this unit. The passive voice extension matters too: was and were trigger the same participle that have and had do, just in a passive construction, so 'were shaken' follows the identical logic as 'had shaken.'
Key terms
- Simple past
- The verb form used alone to show an action already finished, like sank or rose.
- Past participle
- The verb form that must follow a helper verb such as have, had, was, or were, like sunk or risen.
- Helper verb
- A word like have, has, had, was, or were that pairs with a participle to form a complete verb phrase.
- Irregular verb
- A verb that does not form its past tense and participle by simply adding -ed, so its forms must be memorized.
- Passive voice
- A construction using was or were plus a past participle where the subject receives the action rather than performs it.
Watch it explained
- How it worksHow does an irregular verb keep three separate forms, so drink, drank and drunk each have one job?
- How it worksWalk me through spotting a helper verb like 'have' or 'had' as the signal that a past participle is required.
- Worked exampleFind the right form for 'The river had ___ its banks by dawn' choosing among rise, rose and risen.
- Common mistakeWhy isn't 'sunk' interchangeable with 'sank' in 'The boat ___ in twenty minutes'?
- Going furtherWhat changes about a verb form when the helper is 'was' or 'were' rather than 'have' or 'had'?
Check yourself
End of topic.