Educational worksheet focusing on past participle verb forms with a disaster theme.

To solve this worksheet, we need to change the verbs in parentheses into their past participle forms. These sentences use helping verbs like *have*, *has*, *had*, *could have*, or *should have*. When you see these helping verbs, the main verb usually changes to its past participle form (often ending in -ed, -en, or -t).

Here is the step-by-step breakdown for each sentence:

1. know: The past participle of "know" is known.
* *Sentence:* No one could have known...
2. think: The past participle of "think" is thought.
* *Sentence:* None of us would have thought...
3. predict: This is a regular verb, so we add -ed. The past participle is predicted.
* *Sentence:* We could not have predicted...
4. strike: The past participle of "strike" is struck.
* *Sentence:* It was as if lightning had struck...
5. arise: The past participle of "arise" is arisen.
* *Sentence:* This problem should never have arisen...
6. see: The past participle of "see" is seen.
* *Sentence:* But we should have seen...
7. do: The past participle of "do" is done.
* *Sentence:* Someone could have done...
8. find: The past participle of "find" is found.
* *Sentence:* Maybe I could have found...
9. ask: This is a regular verb, so we add -ed. The past participle is asked.
* *Sentence:* Mom could have asked...
10. go: The past participle of "go" is gone.
* *Sentence:* My brother could have gone...
11. get: The past participle of "get" is gotten (in American English) or got (in British English). Since most school worksheets in this format use American English, gotten is the standard answer here.
* *Sentence:* He could have gotten...
12. bring: The past participle of "bring" is brought.
* *Sentence:* He could have brought...
13. choose: The past participle of "choose" is chosen.
* *Sentence:* I should have gone with him and chosen...
14. give: The past participle of "give" is given.
* *Sentence:* ...no one had given...
15. run: The past participle of "run" is run (it stays the same as the base form, but distinct from the past tense "ran").
* *Sentence:* That is why we have now run...

Final Answer:
1. known
2. thought
3. predicted
4. struck
5. arisen
6. seen
7. done
8. found
9. asked
10. gone
11. gotten
12. brought
13. chosen
14. given
15. run