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SAT Standard English Conventions
Understand sentence boundaries, punctuation, agreement, and grammar with free SAT English lessons and examples.
These are BuildSAT teaching examples. Use the study workspace to apply the concepts to official practice questions and review your progress.
Open interactive lessons →Boundaries
Complete sentences and clauses
Identify a complete thought before choosing punctuation.
Independent clause
A clause has a subject and a verb. An independent clause also expresses a complete thought: “The engine stopped.”
Dependent clause
Words such as although, because, if, when, and while can make a clause depend on another clause: “Although the engine stopped” leaves a thought unfinished.
Phrase versus clause
A phrase does not contain its own subject–verb pair. A verb ending in -ing is not automatically a complete verb: “The engine running quietly” is a fragment.
Start with a subject and a predicate
The subject names what a clause is about. The predicate tells what that subject does or is and contains a complete verb. In “The young birds are nesting,” “birds” is the head of the subject and “are nesting” is the complete verb phrase. Descriptive words can lengthen either part without creating another clause.
Completeness is a grammatical relationship
A dependent marker changes the role of a complete-looking clause: “The birds are nesting” makes a statement, but “Because the birds are nesting” gives a reason that needs a main statement. An -ing phrase can describe a noun without asserting anything about it. To diagnose a fragment, ask what main statement the words actually make.
Worked example
Repair: “Because the road was flooded.”
- “The road” is the subject; “was flooded” is the verb phrase.
- “Because” makes this a dependent clause. Add a main clause.
Because the road was flooded, the bus took another route.
Watch for this: Find the main subject and complete verb. Sentence length and capitalization do not make a fragment complete.
Check your understanding
Which option is a complete sentence?
- While the artist was preparing the canvas.
- The artist preparing the canvas.
- The artist prepared the canvas.
- Because the canvas was ready.
Show answer and explanation
Answer: C. “The artist” is the subject and “prepared” is a complete past-tense verb; the thought is complete.
Boundaries
Periods, semicolons, and FANBOYS
Join two complete thoughts without a run-on or comma splice.
Period or semicolon
A period separates two sentences. A semicolon can join two closely related independent clauses without a conjunction. Both sides must stand alone.
Comma + coordinating conjunction
Use a comma before for, and, nor, but, or, yet, or so when that conjunction joins independent clauses. These are the FANBOYS conjunctions.
What cannot do the job
A comma alone cannot normally join independent clauses. A semicolon does not turn a fragment into a complete clause.
A boundary tells the reader how thoughts connect
Two independent clauses each have their own subject and complete verb. Putting a comma between them does not specify a valid sentence boundary. A period separates them completely; a semicolon puts the two complete thoughts in one sentence. A coordinating conjunction can state a relationship such as contrast or consequence.
Do not confuse a shared verb structure with two clauses
“Mina measured the sample and recorded its mass” has one subject governing two verbs. “Mina measured the sample, and Leo recorded its mass” has a new subject after “and,” so there are two independent clauses. Count the clauses before deciding whether the conjunction needs a preceding comma.
Worked example
Join: “The trail was muddy. We continued hiking.”
- Both parts have a subject, a verb, and a complete thought.
- A semicolon works: “The trail was muddy; we continued hiking.”
- To emphasize contrast, use a comma plus “but.”
The trail was muddy, but we continued hiking.
Watch for this: “However” and “therefore” are not FANBOYS. They cannot fix a comma splice by themselves.
Check your understanding
The results were promising____ the researchers repeated the experiment. Which choice correctly fills the blank?
- ,
- ;
- because,
- and,
Show answer and explanation
Answer: B. A semicolon joins the independent clauses “The results were promising” and “the researchers repeated the experiment.”
Boundaries
Commas: introductions, lists, and boundaries
Use commas for structure rather than pauses.
Introductory clauses
A dependent clause placed before the main clause usually takes a separating comma: “After the rain stopped, we left.”
Lists
Commas separate three or more items: “paper, pencils, and folders.” A semicolon can separate list items that already contain commas.
Keep essential parts together
Do not put a comma between a subject and its verb or between a verb and its direct object just because the subject or object is long.
Use commas to mark units, not breathing
The core of a sentence is usually subject → verb → required complement. A comma can mark material before that core, separate items in a series, or enclose an extra description. It should not split the core just because a long subject makes you want to pause while speaking.
An introductory clause has its own structure
“After the meeting ended” includes a subject and verb but depends on the main clause because of “after.” When it comes first, a comma marks its end. Compare “We left after the meeting ended”: an essential following time clause normally does not need a comma before it. Position and function matter.
Worked example
Punctuate: “When the gates opened visitors entered the museum.”
- “When the gates opened” is introductory and dependent.
- “Visitors entered the museum” is the main clause.
- Place the comma between those two units.
When the gates opened, visitors entered the museum.
Watch for this: A natural speaking pause is not a reliable punctuation rule.
Check your understanding
Which sentence is punctuated correctly?
- After the lecture ended, the students asked questions.
- The students, asked questions.
- The lecturer answered, the questions.
- After, the lecture ended the students asked questions.
Show answer and explanation
Answer: A. The introductory dependent clause ends at “ended,” so the comma correctly marks the boundary before the main clause.
Boundaries
Essential and nonessential information
Decide whether a modifier identifies something or adds extra information.
Essential information
A restrictive modifier identifies which person or thing is meant. Do not set it off: “Students who submitted forms may attend.” Only those students qualify.
Nonessential information
An extra detail is set off with paired commas, paired dashes, or parentheses when it interrupts a sentence: “Nora, our captain, spoke.”
Pair the boundaries
If an interruption begins with a comma and continues into the middle of a sentence, it usually needs a closing comma. Match paired dashes with dashes.
Ask whether the reader needs the description to identify the noun
In “The students wearing badges entered,” the modifier selects which students entered. Remove it and the group changes. In “The students, wearing badges, entered,” the sentence presents the badges as an extra description of an already identified group. Punctuation can change meaning, not just appearance.
The removal test checks structure, then meaning
Temporarily remove an interruption and reconnect the remaining words. The sentence should still be grammatical, but that alone is not sufficient: decide whether removing the detail loses information needed to identify the noun. An appositive is a noun phrase that renames another noun, such as “our guide” in “Ava, our guide, spoke.”
Worked example
Add the extra description “a marine biologist” to “Dr. Chen studies coral.”
- The scientist is already identified by name.
- The description interrupts the main clause.
- Put a comma on each side of the extra phrase.
Dr. Chen, a marine biologist, studies coral.
Watch for this: Meaning determines whether information is essential. Do not automatically put commas around every “who” or “which” phrase.
Check your understanding
Maya ____ the team’s captain ____ thanked the volunteers. Which punctuation pair correctly sets off the extra description?
- comma / comma
- semicolon / comma
- no punctuation / semicolon
- colon / colon
Show answer and explanation
Answer: A. Paired commas enclose the nonessential appositive “the team’s captain.” Removing it leaves “Maya thanked the volunteers.”
Boundaries
Colons, dashes, and explanations
Introduce an explanation or list after a complete clause.
Colon
A colon can introduce a list, example, or explanation after an independent clause: “She packed three items: a map, water, and a jacket.” The part after the colon need not be a complete clause.
Single dash
A dash can introduce an emphatic explanation or final addition. As with a colon in this use, first check that the introductory part is complete.
Paired dashes
Two dashes can surround an interruption. This is a different job from one dash introducing a final explanation.
A colon promises an explanation of a complete introduction
Before a colon, the reader should already have a complete independent clause. What follows can then identify, illustrate, or explain it. “She brought these supplies” is complete because “these supplies” is the object. “She brought” is incomplete in this context because the sentence has not yet supplied what she brought.
Different marks can introduce similar information
A single dash may introduce an emphatic final explanation; paired dashes instead enclose an interruption. A semicolon generally joins two independent clauses, whereas a colon can introduce a noun phrase or list after a complete clause. Decide from the structures on both sides, not from the length of the information.
Worked example
Compare “Her supplies included: paper and ink” with “She needed two supplies: paper and ink.”
- “Her supplies included” is incomplete because “included” still needs its object.
- “She needed two supplies” is a complete independent clause.
- Only the second version gives the colon a complete introduction.
She needed two supplies: paper and ink.
Watch for this: A list by itself does not justify a colon. Read the words immediately before the punctuation.
Check your understanding
Which sentence uses a colon correctly?
- The recipe requires: flour, water, and salt.
- The tools were: a saw and a drill.
- Bring the following: a notebook and a pen.
- The scientist: measured the sample.
Show answer and explanation
Answer: C. “Bring the following” is a complete command with an understood subject “you.” A colon can introduce the list.
Form, Structure, and Sense
Apostrophes, plurals, and possession
Distinguish ownership, contractions, and ordinary plurals.
One owner
Add apostrophe + s to most singular nouns: “the student’s notebook.”
Several owners
For a plural ending in s, add an apostrophe after the s: “the students’ notebooks.” For irregular plurals, add ’s: “the children’s books.”
No apostrophe for an ordinary plural
“Three students” is plural, not possessive. “It’s” means “it is” or “it has”; “its” shows possession.
Separate number from ownership
First decide whether a noun names one thing or several. Then ask whether that noun owns or is associated with the following noun. In “the players’ coach,” “players” names multiple owners and “coach” names what belongs to that group. The number of coaches does not determine where the owners’ apostrophe goes.
Apostrophes can also replace missing letters
A contraction combines words: “they’re” replaces “they are,” and “it’s” replaces “it is” or “it has.” Possessive pronouns already indicate ownership, so “its,” “theirs,” and “whose” do not take possession apostrophes. Expand a suspected contraction in the sentence to check whether it fits.
Worked example
Write a sentence about the collars belonging to two dogs.
- Two dogs gives the plural noun “dogs.”
- The collars belong to those dogs, so add an apostrophe after the plural s.
The dogs’ collars were blue.
Watch for this: Test “it’s” by replacing it with “it is” or “it has.” Possessive pronouns such as its, yours, and theirs have no apostrophe.
Check your understanding
Several teachers share one lounge. Which phrase correctly names it?
- the teacher’s lounge
- the teachers’ lounge
- the teachers lounge’s
- the teacher lounge
Show answer and explanation
Answer: B. “Teachers” is plural and ends in s; the apostrophe after the s marks possession by several teachers.
Form, Structure, and Sense
Subject–verb agreement
Match the verb to the actual subject, even when other nouns intervene.
Find the head noun
In “The box of old photographs is heavy,” the subject is “box,” not “photographs.” The verb is singular.
Compound and indefinite subjects
Subjects joined by “and” are usually plural. Words such as each, either, neither, and everyone are singular when they function as the subject.
Inverted sentences
In “On the shelf are three books,” the subject follows the verb. “Books” still requires “are.”
The subject controls number
Agreement means that a finite verb has the grammatical number required by its subject. In the present tense, many singular third-person verbs end in s (“she writes”), while the corresponding plural does not (“they write”). Do not use noun endings as a shortcut: the s on a verb often signals singular, not plural.
Strip away distractions before matching
Prepositional phrases, appositives, and relative clauses can place another noun next to the main verb. Bracket those descriptions and reconnect the head subject to its verb. If a relative pronoun such as “which” is itself the subject of a clause, determine the noun it refers to before choosing that clause’s verb.
Worked example
Choose: “Each of the instruments (needs / need) tuning.”
- Cross out the descriptive phrase “of the instruments.”
- The subject “Each” is singular.
- Use the singular present-tense verb “needs.”
Each of the instruments needs tuning.
Watch for this: Do not let the noun closest to the blank control the verb automatically.
Check your understanding
The list of recommended books ____ on the desk.
- are
- have been
- is
- were
Show answer and explanation
Answer: C. The singular subject “list” takes “is.” “Of recommended books” does not change the subject’s number.
Form, Structure, and Sense
Verb tense and verb forms
Use time clues and distinguish main verbs from participles.
Use the timeline
Keep tense consistent when actions share a time frame. Change tense when the meaning calls for it: a past discovery can still explain a present fact.
Perfect forms
“Has/have + past participle” connects a past action or state to the present. “Had + past participle” can mark an action completed before another past event.
Complete the verb
“Designed” can be a complete past-tense verb. “Designing” and “to design” alone do not serve as the main verb in an ordinary declarative clause.
Tense locates an action; aspect describes its relationship to time
Simple past presents an event in the past (“worked”). Present perfect links earlier activity to the present (“has worked”). Past perfect places an event before another past reference point (“had worked”). Progressive forms use a form of be plus an -ing participle to show ongoing activity.
A verb-looking word may not function as the main verb
A finite verb can anchor a clause and express tense or modality: “works,” “worked,” “can work.” An infinitive (“to work”) or participle (“working”) often serves as a modifier or part of a larger construction. Ask whether the sentence already has a main verb before inserting another finite verb.
Worked example
Complete: “By the time the guests arrived, the chef ____ the meal.”
- The arrival happened in the past.
- The meal was already completed before that arrival.
- Use the past perfect form to make the order explicit.
By the time the guests arrived, the chef had prepared the meal.
Watch for this: Do not force every verb in a passage into the same tense; follow the actual time relationships.
Check your understanding
Yesterday, the scientist ____ the sample and recorded the result.
- examines
- examining
- to examine
- examined
Show answer and explanation
Answer: D. “Examined” matches both the past time marker “Yesterday” and the coordinated verb “recorded.”
Form, Structure, and Sense
Pronouns and clear references
Choose a pronoun with the right role and a clear antecedent.
Antecedent
A pronoun refers to a noun or noun phrase. Its reference should be clear: if “she” could mean either of two people, revise the sentence.
Case
Use subject forms such as I, he, she, and they for subjects. Use object forms such as me, him, her, and them after verbs and prepositions.
Agreement and possession
Match person and number to the intended referent. Distinguish “their” (possession), “there” (place/existence), and “they’re” (they are).
A pronoun must point to the intended referent
The antecedent is the noun or idea a pronoun stands for. Track it across sentence boundaries and check person and number. A plural object requires an appropriate plural reference; a singular object requires a singular reference. Singular “they” can refer to one person, so determine the actual referent instead of applying an oversimplified blanket ban.
Number and case solve different problems
Number asks whether the pronoun represents one or more referents. Case asks its job in the clause: “she” can be a subject, “her” can be an object, and “her book” uses a possessive form. When two names or pronouns are joined, temporarily remove one to hear the remaining pronoun’s grammatical role.
Worked example
Choose: “The instructor spoke to Elena and (I / me).”
- The phrase comes after the preposition “to,” so it needs an object.
- Temporarily remove “Elena and”: “spoke to me” is the correct structure.
The instructor spoke to Elena and me.
Watch for this: Check the pronoun’s role in its own clause. The presence of another person’s name does not change subject/object case.
Check your understanding
The coach gave the instructions to Jordan and ____.
- I
- me
- my
- mine
Show answer and explanation
Answer: B. “Me” is the object form needed after the preposition “to,” even in a compound object.
Form, Structure, and Sense
Modifiers and logical placement
Put descriptions next to the person or thing they describe.
Introductory modifiers
The subject immediately after an introductory descriptive phrase should name its logical actor: “Carrying the microscope, Lena entered.”
Dangling modifiers
“Carrying the microscope, the door opened” wrongly suggests that the door carried it. The intended actor is missing from the subject position.
Placement changes meaning
“Only Lena read three chapters” limits who read. “Lena read only three chapters” limits how much she read. Place limiting words carefully.
A modifier adds information to something else
Adjectives describe nouns; adverbs often describe verbs, adjectives, or other adverbs; entire phrases can modify a noun or clause. The reader needs to know what receives that description. Put a modifier close enough to its target that the grammatical structure and the intended meaning agree.
An opening participial phrase borrows the subject that follows
In “Walking toward the station, Leo checked the time,” the main subject Leo is understood to be walking. If the main subject were “the time,” the sentence would attach the action to the wrong thing. Fix the subject or turn the opening into a clause that explicitly names its actor.
Worked example
Repair: “After studying all evening, the test seemed easier to Omar.”
- The introductory phrase describes the person studying.
- The subject after the comma is “the test,” which cannot study.
- Make Omar the main-clause subject.
After studying all evening, Omar found the test easier.
Watch for this: Identify who or what is doing the action in the introductory phrase before reading the answer choices.
Check your understanding
Which sentence attaches its opening modifier correctly?
- Painted bright yellow, the visitors admired the house.
- Painted bright yellow, the house attracted visitors.
- Painted bright yellow, there were many visitors.
- Painted bright yellow, admiration for the house grew.
Show answer and explanation
Answer: B. The subject “house” is the thing painted bright yellow, so the modifier attaches logically.
Form, Structure, and Sense
Parallel structure
Use matching grammatical forms for ideas with equal roles.
Lists and coordinated ideas
Keep list items in the same pattern: “reading, hiking, and swimming.”
Paired constructions
Structures such as both…and, either…or, and not only…but also should connect grammatically matching elements.
Compare the function
Matching does not mean every word has the same ending. The items need equivalent grammatical roles within the sentence.
Equal roles need compatible grammatical structures
A list gives several items the same job in a sentence. If a verb takes three -ing phrases as its objects, each item should fit that job. Parallelism makes the shared structure easy to recognize; it does not require identical words or identical lengths.
Find the shared introduction
Read each item with the words before the list. In “She hopes to learn, to practice, and to improve,” every item completes “She hopes.” A shared “to” may also govern all three base verbs: “She hopes to learn, practice, and improve.” A mixture is wrong when it breaks the required grammatical role.
Worked example
Repair: “The role involves planning events, managing budgets, and to train volunteers.”
- The first two items are -ing phrases functioning as objects of “involves.”
- Change the infinitive “to train” to the matching -ing form.
The role involves planning events, managing budgets, and training volunteers.
Watch for this: Read the words before and after “and” or “or” together to expose a broken pattern.
Check your understanding
The internship taught her to analyze data, to write reports, and ____.
- presenting findings
- findings were presented
- to present findings
- presentation of findings
Show answer and explanation
Answer: C. “To present findings” matches “to analyze data” and “to write reports.”
Form, Structure, and Sense
Logical comparisons
Compare equivalent things and choose the right comparison form.
Like with like
Compare a city’s population to another population, not to another city: “Riverton’s population is larger than Oakdale’s.”
Comparative and superlative
Use a comparative such as “taller” when comparing two. Use a superlative such as “tallest” to identify the extreme in a group of three or more.
Avoid doubled forms
Use “more efficient” or “better,” not “more better.” Make the group being compared unambiguous.
Name the category on both sides
A comparison is meaningful only when the two things fit the intended category. “The population of City A exceeds City B” compares a population with a place. Repeating “the population of,” using “that of,” or using a possessive can restore the intended population-to-population comparison.
Pronouns can stand for a repeated noun
Use “that” to replace a singular comparison noun and “those” for a plural one. In “The leaves of this plant are larger than those of that plant,” “those” stands for “leaves.” Expand the substitute mentally to verify that the two sides still refer to equivalent things.
Worked example
Repair: “The wings of an eagle are longer than a sparrow.”
- The subject of the comparison is “wings.”
- The second side must also identify wings.
- Use “those of” to refer back to plural “wings.”
The wings of an eagle are longer than those of a sparrow.
Watch for this: Ask, “Exactly what two things are being compared?” before choosing the shorter-sounding answer.
Check your understanding
The climate of Coastville is milder than ____.
- Hilltown
- that of Hilltown
- the people of Hilltown
- Hilltown is
Show answer and explanation
Answer: B. “That of Hilltown” means “the climate of Hilltown,” creating a climate-to-climate comparison.
Put the ideas into practice
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