Question type
Comma rules on the SAT: asides, introductions and lists
Commas on the SAT do three jobs: they enclose nonessential information (an aside opened with a comma must close with one), they follow an introductory phrase or clause, and they separate items in a list. The most common trap is the aside that is opened and never closed.
The key in these questions is a comma: one that closes an aside, follows an introduction, or separates list items.
College Board's question bank has 42 of these and labels most of them Easy or Medium, but real test-takers miss the closing comma of an aside more often than its label suggests.
- 42 in College Board's question bank, 21% rated Hard
- Reading it aloud partly helps
Why students miss it
The unclosed aside: "Petra, the Nabataean capital carved into the cliffs of southern Jordan received" needs a comma after Jordan.
A semicolon or colon where the aside should close.
Missing the introductory clause: "Because the bay funnels the water into a narrowing channel, the tides" needs a comma after channel.
How to spot it
- A comma earlier in the sentence that opens an aside.
- A sentence that starts with "Because", "When", "Although" or a long phrase.
- Choices that differ only by a comma, semicolon or colon after one word.
The method
What is the comma for?
Look back from the blank for an opening comma or an introductory clause.
- An aside opened with a comma
- close it with a comma.
- Introductory clause ends at the blank
- comma.
- Neither
- the comma may be the trap; see unnecessary punctuation.
Does reading it aloud help?
You can hear where an aside ends, but you also hear pauses where no comma belongs.
- Read the sentence without the aside. If it still works, the aside needs commas on both sides.
Two real questions
From the 1500prep bank, the way the app shows them. Answer first, then open the explanation.
Medieval Icelandic farmhouses, whose thick walls were assembled from layered blocks of sod around a modest wooden retained heat remarkably well through the long, dark subarctic winters. Because the grass-covered sod gradually decomposed, however, builders periodically replaced entire sections, so a single dwelling might be reconstructed several times across many generations.
Which choice completes the text so that it conforms to the conventions of Standard English?
Show the answer and explanationThe answer: frame,
Twice each day the Atlantic Ocean drives an enormous volume of seawater toward Nova Scotia. Because the Bay of Fundy funnels that water into a steadily narrowing tides there can rise more than sixteen meters, an extraordinary variation that regularly strands fishing vessels on bare mud flats.
Which choice completes the text so that it conforms to the conventions of Standard English?
Show the answer and explanationThe answer: channel, the
Questions students ask
How do you know if information is nonessential?
Remove it. If the sentence still makes sense and says the same main thing, the information is nonessential and needs commas on both sides.
Do you need a comma after an introductory clause?
Yes, on the SAT: a clause starting with because, when, although or since that opens the sentence is followed by a comma.
Practise this type until it is automatic
Five more comma questions, checked instantly, with every wrong choice explained. Free, no card.