Pentru elevii români: Regulile virgulei din engleză diferă de cele din română: în română, în general, nu se pune virgulă înainte de „și”, pe când în engleză două propoziții independente legate prin „and” primesc de obicei virgulă înainte de „and”. În plus, engleza standard nu acceptă două propoziții independente legate doar prin virgulă (comma splice), construcție perfect firească în română („Am venit, am văzut, am învins”).
What the SAT tests here
The Standard English Conventions domain has two skills: Boundaries (punctuation that separates or joins parts of a sentence) and Form, Structure, and Sense (agreement, verb forms, pronouns, possessives, modifiers). This lesson covers Boundaries.
Every Boundaries question looks the same: a short text with a blank and the prompt "Which choice completes the text so that it conforms to the conventions of Standard English?" The four choices contain the same words with different punctuation. Your job is to identify the grammatical structure on each side of the blank.
Key rules
1. Joining two independent clauses. An independent clause (IC) has a subject and a verb and can stand alone as a sentence. To join two ICs, use:
| Correct | Example |
|---|---|
| Period | The lab closed. The staff went home. |
| Semicolon | The lab closed; the staff went home. |
| Comma + FANBOYS (for, and, nor, but, or, yet, so) | The lab closed, and the staff went home. |
| Colon or dash (when the second clause explains or expands the first) | The lab closed early: a storm had cut the power. |
Wrong: a comma alone (comma splice) or no punctuation at all (run-on).
2. Conjunctive adverbs are not conjunctions. Words like however, therefore, moreover, consequently, thus, nevertheless, and for example cannot join two ICs with commas alone.
- Correct: The data were incomplete; however, the trend was clear.
- Correct: The data were incomplete. However, the trend was clear.
- Wrong: The data were incomplete, however, the trend was clear.
- Inside one clause, use commas: The trend, however, was clear.
3. Dependent clauses. A clause starting with because, although, when, while, since, if cannot stand alone. Do not attach it with a semicolon. When it comes first, follow it with a comma: Although the lab closed, the staff stayed.
4. Nonessential elements need a matching pair. Extra information that could be removed without breaking the sentence is set off by two commas, two dashes, or two parentheses, never a mix:
- Ion Creangă**,** a nineteenth-century writer**,** wrote many famous stories.
- Ion Creangă — a nineteenth-century writer — wrote many famous stories.
5. Essential elements take no commas. If the information identifies which one, do not punctuate it. A title or description with the directly before a name is essential: the writer Ion Creangă, the chemist Marie Curie. Clauses beginning with that are essential and take no comma.
6. Colons and dashes must follow a complete independent clause. They can introduce a list, an explanation, or an example. Never place a colon after such as, including, a verb, or a preposition.
7. No single comma between core parts. Do not separate a subject from its verb or a verb from its object with one comma.
Worked examples
Example 1.
The bridge opened to traffic in remained the longest suspension bridge in the region for decades.
A) 1932 it B) 1932, it C) 1932; it D) 1932 and, it
Both sides are independent clauses ("The bridge opened..." and "it remained..."). A is a run-on, B is a comma splice, and D misplaces the comma. C joins two ICs with a semicolon. (A choice with ", and it" would also be correct, but only one correct option appears on the test.)
Example 2.
Astronomer Priya Nair, who spent a decade mapping faint dwarf argues that many more of these galaxies remain undetected.
A) galaxies B) galaxies, C) galaxies; D) galaxies—
The clause "who spent a decade mapping faint dwarf galaxies" is nonessential, and it opened with a comma after "Nair." It must close with a comma. B. Note that without the closing comma, the sentence would wrongly appear to say that the galaxies argue.
Example 3.
The first trial of the vaccine produced encouraging researchers caution that a much larger study is needed.
A) results, however, B) results; however, C) results however D) results, however
Two ICs are joined by the conjunctive adverb however. It needs a semicolon (or period) before it and a comma after it. B.
Test-taking strategy
- Find the blank and split the sentence there. Ask: is the part before the blank a complete IC? Is the part after it?
- IC + IC: period, semicolon, comma + FANBOYS, or colon/dash.
- IC + non-IC: comma, colon, dash, or nothing, depending on the structure; never a semicolon.
- Look backward for an opening comma or dash. If the sentence already has one before a nonessential phrase, the blank probably needs its matching partner.
- Eliminate duplicates. A period and a semicolon do the same job between two ICs, so if both appear in otherwise identical choices, neither can be uniquely correct; look again at the structure.
- When in doubt, choose less punctuation, unless a rule clearly requires a mark. Unnecessary commas are one of the most common wrong answers.
Common traps
- Comma splices that sound natural when read aloud (and feel natural to Romanian speakers).
- "However" with commas only between two complete clauses.
- Mismatched pairs: an opening dash with a closing comma.
- Colon after "such as" or "including." She studied several languages, such as: French is wrong.
- Commas around essential names: The novelist, Ion Creangă, wrote... is wrong on the SAT.
- Semicolon before a dependent clause: She stayed late; because the lab was busy is wrong.
Summary
Boundaries questions test structure, not style. Identify whether each side of the blank is an independent clause. Join two ICs with a period, semicolon, comma + FANBOYS, or colon/dash; treat however and similar words as adverbs that need a semicolon or period before them; enclose nonessential elements with a matching pair; and leave essential information unpunctuated. Practice these patterns until you can spot them in seconds.