On the test
Usually questions 15 to 21 of each Reading and Writing module (27 questions per module, 2 modules). Conventions questions are sorted by difficulty, not by rule.
11 to 15 questions in the whole test (about 7 in each module). Usually questions 15 to 21 of each module.
How I approached it
A small story from Aime
When I think about Boundaries, I think about the fences between farm plots in my home area. Each plot belongs to one family and has its own crop. A fence tells you where one plot ends and the next begins. If the fence is missing, the crops mix and nobody knows who owns what. If you put a fence in the middle of one plot, you cut a healthy field into useless pieces. I approach these questions the same way: first I find each complete idea, which is one plot, and then I check the fence between them. On the SAT, a sentence is a plot, and punctuation is the fence. Your job is to put the right fence in the right place, and nowhere else.
Punctuation looks like a hundred small rules, but the SAT tests only a few, again and again. Learn the plots and the fences and these become some of the most reliable points you can win.
What is inside this part
Choosing the correct way to connect two complete sentences: period, semicolon, comma with a joining word, or colon.
Comma splices · Run-on sentences · Semicolons and transitions
Using commas or dashes for words that come before the main clause or interrupt it.
Comma after an introduction · Matching pairs of commas or dashes · Who and which clauses
Using a colon or dash after a complete sentence to bring in a list, an explanation or an example.
Colon before a list · Colon before an explanation · Single dash for an added thought
Knowing when no punctuation is the right answer because the words belong together.
No comma between subject and verb · No colon after including or such as · No comma after because or that
Using semicolons to separate list items that already contain commas.
Places with descriptions · Names with titles
How to know a question is from this part
A sentence with a blank where the choices differ mostly in punctuation, with almost the same words.
- The question says: 'Which choice completes the text so that it conforms to the conventions of Standard English?'
- The four choices have the same words but different commas, semicolons, colons, dashes or periods
- One choice often has no punctuation at all
- The blank sits between two parts of a sentence, or around extra information
- If the choices are different words, it is not Boundaries
The lesson
1. What Boundaries questions are
Boundaries questions test punctuation: commas, semicolons, colons, dashes and periods. The question says: 'Which choice completes the text so that it conforms to the conventions of Standard English?'
The four choices are the same words with different punctuation between them. You choose the correct punctuation.
So you do not need to know hard words. You need to know where an idea starts and ends.
2. The key tool: independent and dependent clauses
A clause is a group of words with a subject (who or what) and a verb (the action or state).
An independent clause can stand alone as a full sentence. Example: The market opens early.
A dependent clause has a subject and a verb, but it starts with a word like because, although, when, if, which or who, and it cannot stand alone. Example: Because the road was flooded.
A phrase has no subject-verb pair. Example: After the rain, or: a notebook, a pen, and a ruler.
Almost every Boundaries question is solved by marking each part as independent clause (IC), dependent clause (DC) or phrase.
3. Rule 1: Joining two independent clauses
Two independent clauses (IC + IC) can be joined in these ways only:
a) A period: IC. IC.
b) A semicolon: IC; IC.
c) A comma plus a joining word (and, but, or, so, for, nor, yet): IC, and IC.
d) A colon, when the second clause explains or gives an example of the first: IC: IC.
A comma alone is NOT allowed. That mistake is called a comma splice. No punctuation at all is also wrong. That is a run-on.
The shop closes at five ______ the owner stays to count the money. Choices: A) five the owner B) five, the owner C) five; the owner D) five and, the owner
Show the steps
- Before the blank: The shop closes at five (IC).
- After the blank: the owner stays to count the money (IC).
- IC + IC can take a semicolon, a period, or a comma plus a joining word.
- B is a comma splice, A is a run-on, D misplaces the comma.
C
4. Rule 2: Introductory and extra information
When a dependent clause or phrase comes BEFORE an independent clause, put a comma after it: Because the road was flooded, the bus took a longer way.
When extra information (not needed to know which person or thing) is inside a sentence, set it off with a pair of commas or a pair of dashes: The teacher, who taught for twenty years, retired.
The pair must match. Comma with comma, dash with dash. Never mix them. If you start with one, you must close with the same one.
Do not put a single comma between a subject and its verb. But a matching pair is allowed around extra information that comes in between, like this: The principal, along with two teachers, arrived early.
After the long rain ______ the river rose above the bridge. Choices: A) rain the river B) rain, the river C) rain; the river D) rain: the river
Show the steps
- After the long rain is a phrase, not a full sentence.
- A phrase before a main clause is followed by a comma.
- A semicolon or colon would need a full sentence before it.
- B has the comma.
B
5. Rule 3: Colons and dashes
A colon (:) must come after a COMPLETE sentence (independent clause). After the colon you can put a list, an explanation, or an example.
Wrong: She bought: a notebook and a pen. (the part before the colon is not complete). Right: She bought three things: a notebook, a pen and a ruler.
A single dash can also come after a complete sentence to add something. A pair of dashes surrounds extra information, like a pair of commas, but stronger.
A semicolon must have an independent clause on BOTH sides, with one exception: it can separate items in a list when the items already contain commas.
I need only one thing from the market ______ fresh tomatoes. Choices: A) market: fresh B) market; fresh C) market, and fresh D) market fresh
Show the steps
- Before the blank is a complete sentence.
- After it comes the answer to 'what thing?', so the colon introduces it.
- A semicolon needs a full clause after it, and fresh tomatoes is not one.
- A is right.
A
6. Rule 4: Transition words in the middle
Words like however, therefore, for example, and moreover are not joining words. They do not join two independent clauses by themselves.
If you have IC and then a transition word and then another IC, use a semicolon before the transition word and a comma after it: The plan failed; however, we tried again.
A comma before the word is a comma splice. A period before the word also works: The plan failed. However, we tried again.
The first test was easy ______ however, the second was very hard. Choices: A) easy, however, B) easy; however, C) easy however; D) easy however,
Show the steps
- Before: The first test was easy (IC). After: the second was very hard (IC).
- However is a transition word, so it cannot join the two clauses with only a comma.
- Use a semicolon before it and a comma after it.
- B is the only one.
B
7. Rule 5: Do not break what belongs together
Do not put a comma between a subject and its verb, between a verb and its object, or after a word like because, that or and when it starts the clause.
Do not use a colon or a semicolon after a word like including, such as, because or that.
If the choices include a plain 'no punctuation' option, it is correct when the sentence flows without a break.
8. The method
Step 1. Find the punctuation spot. Read the words before it and after it.
Step 2. Mark each side: IC, DC or phrase.
Step 3. Use the rule table: IC + IC, DC + IC, extra information, list, or transition.
Step 4. Cross out the choices that break the rule. Check that pairs match.
Step 5. Read the sentence with your choice. If it is smooth, you are done.
9. Common traps
Trap 1: Choosing a comma because it 'feels like a pause'. The test follows rules, not breathing.
Trap 2: Long sentences. Cross out the extra phrases to see the real subject and verb.
Trap 3: The semicolon trap. A semicolon before 'and' or 'but' is almost always wrong, unless you are separating items in a long list.
Trap 4: Pairs that do not match. One dash and one comma is always wrong.
Trap 5: A colon after an incomplete sentence.
See it
- 1Find the punctuation spot
- 2Label the words before and after: IC, DC or phrase
- 3Pick the rule that fits that pair
- 4Cross out choices that break the rule
- 5Read it again to check
| Left side | Right side | Allowed punctuation |
|---|---|---|
| Independent clause | Independent clause | period, semicolon, comma + and/but/so, or colon |
| Dependent clause or phrase | Independent clause | comma |
| Independent clause | List or explanation | colon |
| Independent clause | Transition + independent clause | semicolon before, comma after |
| Subject | Verb | no punctuation, or a matching pair for extra information |
- It rained all night, the roads were muddy.
- She wanted to go, her parents said no.
- The plan failed, however, we tried again.
- It rained all night; the roads were muddy.
- She wanted to go, but her parents said no.
- The plan failed; however, we tried again.
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