2 and 3 are incorrect; the comma after "mats" is necessary because it's a compound sentence.
I think 1 is better than 4 because I don't think the comma after "homework" is needed.
Which of the following sentences is punctuated correctly?
Group of answer choices
Jimmy does his math homework as Lenny starts stretching on the gymnastic mats, and Larry hides behind the bleachers eating peanut butter and jelly sandwiches.
Jimmy does his math homework as Lenny starts stretching on the gymnastic mats and Larry hides behind the bleachers eating peanut butter and jelly sandwiches.
Jimmy does his math homework, as Lenny starts stretching on the gymnastic mats and Larry hides behind the bleachers eating peanut butter and jelly sandwiches.
Jimmy does, his math homework, as Lenny starts stretching on the gymnastic mats, and Larry hides behind the bleachers, eating peanut butter and jelly sandwiches.
1 answer