Which sentence contains a punctuation error?

Which sentence contains a punctuation error?

• A. Juan ran and ran but, he was unable to finish first in the race.
• B. The family decided to travel to Russia during the cold, windy winter months.
• C. Cypress, Texas has see increase in population, since 2010.
• D. James saw that he was not doing well with his homework, so he decided to study more.

Answer: (A)

When two independent thoughts are connected with a coordinating conjunction like but, you put a comma before the conjunction and start the second idea right after it. Don’t place a comma immediately after the conjunction. In this sentence, there are two complete ideas: “Juan ran and ran” and “he was unable to finish first in the race.” They should be joined as “Juan ran and ran, but he was unable to finish first in the race.” The error is the comma after but—“but, he was…”—which breaks the flow of the second clause and isn’t needed. So the punctuation problem shown here is the misplaced comma right after the conjunction. The other sentences don’t illustrate this exact issue: one uses a standard comma to separate coordinate adjectives or to connect clauses in a typical way, and another correctly uses a comma before so to link two main clauses. The misplaced comma after but is the clear, typical punctuation mistake being tested.

When two independent thoughts are connected with a coordinating conjunction like but, you put a comma before the conjunction and start the second idea right after it. Don’t place a comma immediately after the conjunction. In this sentence, there are two complete ideas: “Juan ran and ran” and “he was unable to finish first in the race.” They should be joined as “Juan ran and ran, but he was unable to finish first in the race.” The error is the comma after but—“but, he was…”—which breaks the flow of the second clause and isn’t needed. So the punctuation problem shown here is the misplaced comma right after the conjunction.

The other sentences don’t illustrate this exact issue: one uses a standard comma to separate coordinate adjectives or to connect clauses in a typical way, and another correctly uses a comma before so to link two main clauses. The misplaced comma after but is the clear, typical punctuation mistake being tested.