Why this matters on the SAT
Many SAT sentences include extra information: a phrase or clause they could do without, set off by a pair of commas, dashes or parentheses. The blank sits at one end of it, and the mark at the other end is often far away. So the real question has two parts: where does the extra information start, and where does it end? These are among the most common punctuation questions on the test, and once you can see both ends, the mark at the blank follows.
Solution to the example
The comma after Bridge opens one of the longest bridges in Europe, a phrase that renames the bridge and ends right before the main verb, was completed. Cross it out, and the sentence still works, so it's extra information, and the comma that opened it needs a comma to close it. The answer is B. C tempts most, because the comma that opened the phrase is seven words back, but with no mark the phrase never closes. A dash (A) or a semicolon (D) doesn't match the comma that opened it.
SAT example
Portugal's Vasco da Gama Bridge, one of the longest bridges in ___ was completed in time for the 1998 World's Fair held in Lisbon.
Which choice completes the text so that it conforms to the conventions of Standard English?
Europe—
Europe,
Europe
Europe;
Many sentences carry extra information: a detail the sentence could do without, often about the word right before it. Grammar books call a piece of extra information a parenthetical element; this lesson calls it an insert. Cross out the insert, and a complete, correct sentence is left. Every question in this lesson comes back to that test.
In the examples, both ends of the insert are bold, words a test removes are struck through, and the subject and main verb are underlined.
Inserts come in a few shapes, and the SAT uses all of them:
A which, who or whose clause adds a fact about a noun, a renaming phrase gives it another name, and an -ed or -ing phrase describes it. Grammar books call a renaming phrase an appositive. An interrupter like according to local sailors breaks in with a side comment.
Some words only look extra, such as a name or a who clause that tells you which one; the next lesson shows how to tell what's essential from what's extra.
When a comma opens an insert in the middle of a sentence, a second comma has to close it. An insert that follows a subject usually ends right before that subject's main verb.
The missing closing comma is the most common trap in these questions. By the time you reach the end of the insert, the comma that opened it is far behind you, and the words before the blank sound finished. Either end can be the blank, and one comma alone, on either side, leaves the pair broken.
To find the end, look for the subject's own verb. A which clause has a verb of its own, was built, but that verb goes with which, not with the lighthouse. Who and whose clauses work the same way. The lighthouse's main verb is guides, so the clause ends right before it. That's where the closing comma usually goes, even twenty words on.
Not every insert sits between a subject and its verb. One can sit right after “and”, before the verb that “and” brings in, or end before a phrase that carries the sentence on, such as a to phrase. Wherever it sits, an insert ends where the sentence picks up again: cross it out, and what's left must read as one sentence.
Some choices add a verb at the blank. In The ______ built in 1871, guides fishing boats into the harbor, a choice like lighthouse was turns the insert into the main part of the sentence. Cross out the insert first: the lighthouse already has its main verb, guides, so was would be one too many, and lighthouse, opens the insert that the comma after 1871 closes.
In the middle of a sentence, a semicolon, a colon or “and” can't close an insert. Only the mark that opened it can.
A semicolon or a colon looks like a clean break, so it tempts most when the insert is long. But a semicolon works only where a period would, and a colon needs a full sentence before it too. The words before that mark aren't a full sentence yet: The lighthouse, which was built in 1871 has no main verb. After a full sentence, a colon has other jobs, which come later in the course.
“And” fails another way: it pulls guides into the which clause, so the lighthouse never gets a main verb of its own, and the whole sentence is a fragment.
Comma or no comma at the blank? The museum’s oldest painting, a portrait of the town’s founder ______ hangs in the main hall.
Try it on this question: find the comma that opens the insert, then find where it ends, right before the subject's own verb.
Practice problem
In her 2021 memoir, the chef, reflecting on her early years growing up on a small _____ recounts mornings spent milking goats and evenings perfecting recipes over a wood-burning stove.
Which choice completes the text so that it conforms to the conventions of Standard English?
Dashes can set off an insert too, and so can parentheses. In the middle of a sentence, whichever mark opens the insert has to close it: a dash closes a dash, and a closing parenthesis closes an opening one.
To close an insert, look back for the mark that opened it, and use the same one. A matching pair of any of the three is correct, so the choices turn on the match. A transition such as “however” is set off by commas only, as lesson 7 shows.
Parentheses rarely come up on the test. They set off an insert by themselves, so a comma follows “)” only where the sentence would need one with the parentheses gone, as in Although it was built in 1871 (and rebuilt in 1904), the lighthouse still guides fishing boats into the harbor.
When the blank comes first, read ahead for the mark that closes the insert, and open it with the same one.
A comma before a stone tower looks natural on its own. The dash after point is what decides it.
Try it on this question: find the mark after the insert before you look at the choices.
Practice problem
Founded in 1607, the English settlement of _____ small fort along the James River—depended heavily on supplies shipped from England during its earliest years.
Which choice completes the text so that it conforms to the conventions of Standard English?
So far, every insert sat in the middle of a sentence. At the start or end of a sentence, one mark does the job, because the sentence's edge does the other half: one comma closes an insert that opens a sentence, and one mark, usually a comma, opens an insert that ends one.
This answers the question lesson 2 left open. A part that can't stand alone attaches to a full sentence with a comma or no mark, and when it adds extra information after a full sentence, it takes a comma. A part that finishes what the sentence says takes no mark instead; lesson 5 covers those.
A stone tower built in 1871 can't stand alone: it has no main verb, since built only describes (was built in 1871). A period or a semicolon would leave it a fragment, and since they do the same job, when both appear in the choices, they cancel out.
An insert at the end can hold a verb and still not stand alone:
Left goes with that, the way a verb goes with which. A change never gets a main verb of its own, so a period before it would leave a fragment.
A dash can open an insert at the end of a sentence too, and then whatever ends the sentence closes it, even a semicolon before a second sentence, because a closing dash can't also mark where one sentence ends:
When a full sentence ends with a quotation, the comma that opens the insert goes inside the closing quotation mark: The keeper's log calls the light “a promise to every boat,” a line still painted above the cottage door.
A period or a comma at the blank? The town rebuilt the old pier in 2015 ______ a project paid for by the fishing cooperative.
In this question, check whether the sentence is full before the blank, then ask whether the words after it can stand alone.
Practice problem
In 1922, James Joyce’s novel Ulysses first appeared in print through Shakespeare and _____ Paris bookstore run by Sylvia Beach.
Which choice completes the text so that it conforms to the conventions of Standard English?
Commas, quotation marks or a second insert inside an insert belong to it, so they don't close it. In the middle of a sentence, only the mark that matches the opener does. So the first closing mark you meet may belong to a smaller insert, not the one you're tracking.
A list inside dashes keeps its commas, and a dash still closes it:
The list's commas make one more comma look natural, but a comma can't close what a dash opened.
When one insert opens inside another, the inner one closes first, then the outer one:
The parenthesis opened last, so “)” comes first. Closing the inner insert doesn't close the outer one.
A comma pair can sit inside a comma insert, too. Cross out the inner one first:
The comma after small closes only though small. The whose clause runs on to miles.
An inner insert can even open right after that, so a comma there is right when it starts a pair:
Cross out within a year, and a change that emptied the keeper's cottage is left. Without the comma after that, the comma after year has no partner, and it splits that from its verb, emptied.
In this question, a list sits inside the insert: look back past the list's commas for the mark that opened it.
Practice problem
The composer finished her symphony using field recordings from the Arctic. These field recordings—wind over sea ice, distant whale calls, and the crunch of snow under _____ the piece an unexpectedly intimate texture.
Which choice completes the text so that it conforms to the conventions of Standard English?
Before you match marks, make sure a comma before the blank really opened something. A comma can also close an opening part, or separate the items in a list. To check, cross out from that comma to the blank: if what's left breaks, nothing is open. If it still reads as a sentence, and the comma isn't separating list items, the comma opened an insert.
In the second sentence, After the storm relit the lamp breaks, so the comma only closes the opening part, and no mark goes after keeper.
Once you've found the mark that opened an insert in the middle of a sentence, every choice that closes it with anything else, such as a semicolon, a colon or “and”, goes at once. Most of these questions come down to one pair. That makes one routine for every question in this lesson, the one the worked examples and the practice problems at the end follow:
In four of these five sentences, a closing comma is missing; the other asks whether an insert is open at all. Find where each insert ends, then check your answer.
Where does the closing comma go? The harbor museum, which opened in a former customs house draws thousands of visitors each summer.
Where does the closing comma go? Our guide, a retired ferry captain who had crossed the strait thousands of times knew every rock by name.
Where does the closing comma go? The ferry slowed and, as the fog thickened sounded its horn every minute.
Is an insert open at the blank? After the storm passed, the harbor ______ reopened by noon.
Where does the closing comma go? The keeper’s log, which records every ship (and, on stormy nights, every wave) that passes the point is kept in the museum.
In this question, the comma that opens the insert is more than a dozen words before the blank, and a second pair of commas sits inside it.
Worked example
Japanese American artist Ruth Asawa, whose looped-wire sculptures, though made from ordinary industrial wire, cast intricate patterns of light and ______ conventional distinctions between sculpture and drawing.
Which choice completes the text so that it conforms to the conventions of Standard English?
shadow; challenged
shadow, challenged
shadow—challenged
shadow. She challenged
Step 1
The choices differ in the mark between shadow and challenged, and D also starts a new sentence with She. Look back for an opener: the comma in Asawa, whose opens a whose clause, an insert about Asawa.
A comma opened it, so in the middle of the sentence, a comma has to close it. That rules out C: a dash can't close what a comma opened.
Step 2
Two more commas come before the blank, after sculptures and after wire, and neither closes the whose clause. They're a pair of their own, around though made from ordinary industrial wire, a smaller insert inside the clause. Cross that one out first: whose looped-wire sculptures cast intricate patterns of light and shadow.
Now you can see what cast does. It goes with sculptures, inside the whose clause, so it isn't Asawa's main verb. The clause runs to shadow, and Asawa's main verb comes after the blank: challenged.
Step 3
D is the trap. It tempts if you take the comma after wire as the one that closes the whose clause: then Ruth Asawa … cast intricate patterns of light and shadow looks like a full sentence, and She challenged conventional distinctions would make a good second one. But that comma closes only the smaller insert, and Asawa has no main verb before the blank, so a period leaves Japanese American artist Ruth Asawa, whose … shadow as a fragment.
A fails the same way. A semicolon works only where a period would, and in the middle of a sentence it can't close an insert.
Step 4
Cross out the whole whose clause, and the sentence works, with Ruth Asawa and challenged as its subject and main verb. A comma opened the clause, so a comma closes it. The answer is B.
In this question, two inserts are open when you reach the blank, and the outer one opened more than twenty words earlier.
Worked example
In a lecture on cartography, historian Asha Ndlovu argues that three persistent mistakes—misplaced mountain ranges, invented inland seas, and the “Phantom River” (a waterway copied from one European map to another for nearly two ______ explorers’ routes long after on-the-ground reports contradicted the printed charts.
Which choice completes the text so that it conforms to the conventions of Standard English?
centuries,) influenced
centuries) influenced
centuries), influenced
centuries)—influenced
Step 1
The choices differ in what closes after centuries. Look back, and the nearest opener is a parenthesis: (a waterway copied from one European map to another for nearly two centuries.
Keep looking back, past the quotation marks around Phantom River and the commas of a list, and a dash after mistakes opened that list. Both inserts are still open at the blank.
Step 2
The parenthesis opened inside the dash insert, so it closes first, with “)”. Every choice has one, but two add a comma.
A puts the comma inside the parenthesis, where it closes nothing, and then nothing closes the dash. C puts the comma after “)”, but a comma can't close what a dash opened.
Step 3
B is the trap. Closing the parenthesis feels like closing the insert, and the dash in mistakes—misplaced is far back. But the list and the parenthesis both sit inside the dash insert, and closing the inner insert doesn't close the outer one. B leaves the dash with no partner.
Step 4
D closes the parenthesis, then the dash: centuries)—influenced. Cross out the dash insert, and the clause after argues that works: three persistent mistakes influenced explorers’ routes. Influenced is the verb that goes with mistakes, the subject the dash interrupted. The answer is D.
These five questions mix the cases from every section, so run the routine on each one: find the opener, find the end and cross it out, then match the mark.
Practice problem
In a talk about building materials, architect Lina Kaur described a new kind of concrete that can repair small cracks when exposed to water. This self-healing process, according to _____ reduces the need for frequent repairs in bridges and tunnels.
Which choice completes the text so that it conforms to the conventions of Standard English?
Practice problem
The Northwest Ordinance of 1787 was more than a land policy: it established a framework for expansion that, by organizing territories and outlining a path to _____ shaped how new states entered the Union.
Which choice completes the text so that it conforms to the conventions of Standard English?
Practice problem
Recent field surveys from shaded cacao farms, which link modest amounts of deadwood to more insect-eating birds but not to higher rates of pod ______ the assumption that deadwood mainly shelters pests.
Which choice completes the text so that it conforms to the conventions of Standard English?
Practice problem
Opened in London in 1851, the Great Exhibition of the Works of Industry of All ______ simply the Great Exhibition, as many newspapers called it—filled the Crystal Palace with displays ranging from steam engines to textiles.
Which choice completes the text so that it conforms to the conventions of Standard English?
Practice problem
To estimate how vivid the hand-colored illustrations in an eighteenth-century botanical atlas once were, conservation scientist Leila Morgan compared pigment particles from the pages with recipes recorded in artists' _____ when supplemented by spectral imaging, allowed her to recreate the atlas's original palette digitally.
Which choice completes the text so that it conforms to the conventions of Standard English?
Finish the lesson
Finish the remaining questions correctly to complete this lesson.
Next lesson
Decide whether a name or a “who” clause takes commas.
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