Problem: Produce a sentence that would be considered grammatically acceptable

Answer: The plucky platypus kicked a can of soup from New York to Tucson.


Problem: Produce a sentence that would be considered grammatically unacceptable

Answer: What happened was they knew his parents.


Problem: Produce a sentence that would be considered grammatically acceptable

Answer:
The contestant who won the first prize, who is the judge's brother-in-law, sang dreadfully.