Question

Question was provided via image upload.

Explanation:

Identify the grammatical error in the visible text

The visible text on the right side of the image reads:
"Laughing uncontrollably, ______ finish his own joke."
The introductory phrase "Laughing uncontrollably" is a participial phrase. To avoid a dangling modifier, the subject immediately following the comma must be the person who is performing the action of laughing.

Determine the correct subject to resolve the dangling modifier

The sentence structure requires a subject (such as "he", "the comedian", or a specific name) that can logically perform the action of "laughing uncontrollably" while completing the action "finish his own joke."

Complete the sentence

Using a singular masculine pronoun "he" to match the possessive pronoun "his" in "his own joke" yields:
"Laughing uncontrollably, he could not finish his own joke." (or "he was unable to finish his own joke.")

Answer:

Laughing uncontrollably, <blank>he could not</blank> finish his own joke.