Complete SAT Grammar Rules Featured

Please note that the following rules have been derived from an extensive study of numerous College Board tests, not just the ones in the Blue Book. Some of them may therefore be difficult to apply if you are using a commercially produced prep book (e.g. Kaplan, Princeton Review) whose tests are designed as approximations of the real thing and sometimes do not contain errors in exactly the same format as those created by the College Board. I can guarantee, however, that the following represents a summary of virtually every type of error that appears on the actual Writing section of the SAT.

If you'd like more in-depth explanations of these rules, along with extensive exercises, please consider ordering a copy of The Ultimate Guide to SAT Grammar.


Error-Identification Categories

1) Subject-Verb Agreement

2) Verb Tense

3) Pronoun Case

4) Antecedent Pronoun (Pronoun Agreement)

5) Adjective vs. Adverb

6) Parallelism

7) Prepositions

8) Faulty Comparisons

9) Comparatives vs. Superlatives

10) Double negatives/Double positives

11) Word Pairs

12) Noun Agreement

13) Relative Pronouns

14) Coordinating Conjunctions

15) Usage

16) Redundancy

Note: while other kinds of errors (e.g. misplaced modifiers) may occasionally appear, they are extremely rare and are therefore not covered here. Although you can expect to find errors from a number of categories included in each section, the first four categories (Verb and Pronoun Errors) generally appear most frequently. It is therefore recommended that you take some time to familiarize yourself with the kinds of sentence structures in which they appear. The remaining categories are listed in approximate order frequency.


In the examples below, the correct answers are given in parentheses.

Although some of the examples below are taken from College Board-created questions, the majority are simplified versions intended to illustrate particular grammatical principles.

1) Subject-Verb Agreement

A. Subject – Non-essential clause – Verb

Ex: Galaxies, far from being randomly scattered throughout the galaxy, appears (appear) to be distributed in bubble-shaped patterns.

Whenever you encounter a parenthetical clause (a clause set off by commas that can be removed without affecting the fundamental meaning of the sentence), cross it out and check subject-verb agreement

B. Subject – Prepositional phrase – Verb

A prepositional phrase is, quite simply, a phrase that begins with a preposition (in, on, over, from, to, of, with, etc.). Very often these will be inserted between subjects and verbs to distract from subject-verb disagreements. Prepositional phrases always end when you get to the verb.

Ex: Changes in the balance of trade seems (seem) remote from everyday concerns, but they can drastically affect how we spend our money.

If you don’t see an error the first time you read a sentence, try crossing out prepositional phrases and checking for subject-verb agreement ("Changes...seems remote from everyday concerns..." is much easier to spot).

C. Prepositional Phrase –Verb – Subject

Ex: Along the Loup Canal in Nebraska extends (extend) many lakes, parks, and trails owned and operated by the Loup power district.

When a prepositional phrase is placed first, make sure you identify the complete subject: very often compound subjects (two singular nouns joined by "and") will be used in this construction, which often appears at the end of the Error-Identification section. In such cases, a singular verb will incorrectly replace a plural verb.

Ex: Along the Loup Canal in Nebraska extends (extend) a park and lake owned an operated by the Loup power district.

D. There is/There are, There has/There have

There is/has = Singular noun

There are/have = Plural noun

Ex: There has (have) been many questions raised about the handling of the company’s finances.

E. Neither/Nor + Verb

The verb always agrees with the noun after "nor."

Ex: Neither the park nor the lake are (is) owned by the city.

Since "lake," the noun after "nor," is singular, the verb is singular as well.

On the SAT, singular nouns connected by neither/nor are only incorrectly paired with plural verbs; plural nouns connected by neither/nor are not tested.


-Collective Nouns (e.g. company, school, city, country, committee, jury, agency etc.) = Singular.

-Each, Every, One = Singular

-A number (of) = Plural BUT The number = Singular

-(N)either one OR whether (n)either clearly refers to two singular nouns = Singular

-Gerunds when used as subjects (e.g. Constructing new skyscrapers often takes many months) = Singular.

-What and whether as subjects (e.g. "Whether dogs are capable of experiencing complex emotions is a subject of much debate among experts."); both are singular.


2) Verb Tense

The inclusion of a date or time period in a sentence usually indicates a tense question. If no tense error appears, the answer is likely to be "no error."

A. Tense Consistency

Sentences that start in the past should generally stay in the past; sentences that start in the present should generally stay in the present.

Ex: Since serious drama unaccompanied by music was forbidden in all but two London theatres during the eighteenth century, Queen’s theatre quickly becoming (became) an opera house.

B. Present Perfect vs. Simple Past

These questions are almost always recognizable by the inclusion of a date or a time period in the sentence.  Any sentence that includes a date in the past or mentions a historical period should always contain a verb in the Simple Past (e.g., went, drank, sang), NOT in the Present Perfect (has gone, has drunk, has sung).

Ex: During the nineteenth century, Charles Dickens has become (became) one of the most famous British novelists.

However, sentences containing ‘since’ and ‘for’ require the present perfect (e.g., I have gone to this school since 2005; I have gone to this school for five years).

C. Would vs. Will

Will and Would get switched with one another; if "will" is underlined, stick in "would" and vice-versa

Ex: William Shakespeare, who will (would) become the greatest English dramatist, was born in 1564.

-In general, "would" should not be used in a sentence with present-tense verbs, and "will" should not be used in a sentence with past-tense verbs.

-Do NOT use would or would have in a clause that begins with if:

If he would have arrived (had arrived) at 5pm, I would have been very happy.

D. Gerunds vs. Infinitives

Gerunds and Infinitives are switched with one another

Infinitive replaced with gerund: Though she was one of the few women of her time gaining (to gain) international prominence, Clara Barton would not have described herself as a proponent of women's rights.

Gerund replaced with infinitive: Laryngitis causes the vocal cords and surrounding tissue to swell, thus preventing the vocal cords to move (from moving) freely.

E. Past Participle vs. Simple Past

In these questions, the simple past rather than the past participle will be incorrectly paired with a form of the verb “To Have.”

Ex: My little brother has grew (grown) two inches during the past year.

F. Past Perfect

Past Perfect = Had + Past Participle (e.g. I had seen, I had gone, He had thrown, etc.)

When a sentence contains two actions or events that occurred in the past, the action that occurred first should be in the past perfect

-The phrase ‘by the time’ is usually a tip-off that the past perfect is required.

Ex: By the time it adjourned, the committee made (had made) several important decisions.

Action #1: The committee made several important decisions

Action #2: The committee adjourned

G. The Subjunctive

The subjunctive is tested infrequently but does appear from time to time. It involves expressions of suggestion and necessity. The main change in the present subjunctive comes in the third person singular form of the verb:

Indicative (normal): He arrives home at 5pm.

Subjunctive: It is necessary that he arrive home at 5pm.

The past subjunctive involves hypothetical circumstances; it includes the verb were, regardless of whether the subject is singular or plural.

If he were to arrive at 5pm, I would be very happy.


Were he to arrive at 5pm, I would be very happy.


3) Pronoun Case: I vs. Me, He vs. Him, etc.


-Any pronoun that follows a preposition must be an object pronoun (Me, Her/Him, Us, Them) rather than a subject pronoun (I, She/He, We, They).

-What goes for singular, goes for plural: the SAT will almost always pair a pronoun (I, he, etc.) with "and" + proper name. Cross out "and + name," and you should be able to hear whether there is an error.

Ex: After two weeks, the teacher finally gave Robert and I (me) back the report.

Would you say, ‘The teacher gave I back the report?’ Obviously not -- you'd say "The teacher gave me back the report." So you wouldn’t say ‘the teacher gave Robert and I back the report’ either.

-If the pronoun is not paired with another name, it will be followed by a noun (e.g. To we students, it seems unfair that classes should start at 7:30am.) Cross out the noun, and the error, if there is one, should be obvious. You would say "to us," not "to we," so you would also say "to us students."

Important: Between you and me, NOT Between you and I


4) Antecedent-Pronoun

An antecedent is a noun that a pronoun refers to. In the sentence, “Jamie picked up the ball and threw it,” the ball is the antecedent and it is the pronoun.

One and You



Ex: If one wants to avoid insect invasions, you (one) should refrain from leaving crumbs lying on the floor.

Singular vs. Plural

Singular nouns are referred to by singular pronouns; plural nouns are referred to by plural pronouns.

Any singular noun referring to a person: he or she, his or her

Any singular noun referring to a thing: it or its

Any plural noun referring to person or thing: the or their 

Ex: A person who wishes to become an Olympic-caliber athlete must devote virtually all of their (his or her) time to training.

BUT: People who wish to become an Olympic-caliber athlete must devote virtually all of their time to training.

Missing Antecedent

Any pronoun in a sentence must clearly refer to a noun, pronoun, or gerund. A pronoun cannot refer to an adjective, verb, or any other part of speech.

Ex: Because of extreme weather conditions, starvation exists in some countries where they (people) must struggle to stay alive.

Ex: In the report released by the committee, it stated that the significant budget cuts would be necessary for the following year.

(The report released by the committee stated that significant budget cuts would be necessary for the following year).

Ambiguous Antecedent

Hint: look for two male or female names.

Ex: Afraid that they would be late to the party, Jenny and Kate decided to take her (Kate’s) car rather than walk.

Do So vs. Do it

Do it = Wrong

Do so = Right

Ex: Activists who defend endangered species from poaching do it (so) on the grounds that such animals, once gone, are irreplaceable.

What does ‘it’ refer to in this sentence? Defending endangered species. But since the gerund ‘defending’ doesn’t actually appear in the sentence, ‘it’ has no real antecedent.


For both Subject-Verb Agreement and Pronoun Agreement, be on the lookout for collective nouns such as group, committee, company, jury, city, agency, team, etc. These nouns are always considered singular, and it is not uncommon for the SAT to pair them with plural verbs and pronouns. Whenever one of these words appears, you should immediately be suspicious.

IT = BAD (most likely). If the word “it” is underlined, it’s most likely wrong. Check its antecedent immediately.


5) Adjective vs. Adverb

Adjectives modify nouns (The good boy; The loud noise, etc.)

Adverbs modify verbs and adjectives and usually end in –ly: He speaks slowly; She runs quickly, etc.

On the SAT, adverbs and adjectives are switched only with one another. If an adjective is underlined, stick in the adverb; if an adverb is underlined, stick in the adjective.

Ex: The patient recovered quick (quickly), although he had been very ill earlier in the week.

Ex: Because the man’s clothing seemed oddly (odd), he attracted a number of stares.


6) Parallelism: Lists 

In any given list, each item should be in the exact same format. Either noun, noun, noun, verb, verb, verb, or gerund, gerund, gerund. Any deviation is incorrect.

Ex: Susan likes to run, swim, and going (go) horseback riding.


7) Prepositions/Idioms

Certain expressions always require certain prepositions. For example, one has a familiarity with something, not a familiarity in something. Because they are idiomatic, reposition questions must be done by ear; there is no way to anticipate what preposition will appear on a given test.

Ex: A familiarity in (with) Latin is useful for anyone who wishes to pursue serious study of a modern romance language.


8) Faulty Comparisons

Rule: Compare things to things and people to people.

Note: When faulty comparison questions appear in Fixing Sentences, they will typically be fixed with the phrases that of (singular) or those of (plural)

Ex: In ancient Greece, women were not allowed to vote or hold property, their status differing from slaves (from that of slaves) only in name.

Ex: At the age of twenty-four, playwright Thornton Wilder was balding and bespectacled, and his clothes were like a much older man (like those of a much older man).


9) Comparatives vs. Superlatives (More vs. Most)

More/-er form of adjective = 2 items being compared

Most/-est form of adjective = 3+ items being compared

Ex: Between the tiger and the lion, the tiger is the faster animal, while the hippo is the most (more) ferocious.

Ex: Hurricane Katrina was one of the more (most) destructive storms of the last hundred years.


10) Double Negatives, Double Positives

Double Negative

Ex: There is scarcely/hardly no (any) milk left in the refrigerator.

Double Positive

Ex: Jane thought that Susan's blouse was more prettier (prettier) than her own.


11) Word Pairs

A. Either...Or

Either the politician or his aide will speak to the media this afternoon.

B. Neither...Nor

Neither the politician nor his aide will speak to the media this afternoon.

C. Not only...But Also

Not only the politician but also his aide will speak to the media this afternoon.

D. Both...And

Both the politician and his aide will speak to the media this afternoon.

E. Between…And (never "Between...Or")

Between the politician and his aide, the latter is far more interesting to listen to.

E. As...As

The aide is as interesting a speaker as the politician.

F. More/Less…Than

The politician’s aid is a more interesting speaker than the politician himself.

G. So/Such…That

The politician was such a boring speaker that half the audience fell asleep.

H. From…To

The politician’s speech covered topics ranging from the economy to the environment.

I. Just as…So (Rare)

Just as the politician’s speech put half the audience to sleep, so did the commentator’s remarks cause the other half to begin yawning.

J. At once...And (Rare, usually correct when it appears)

The politician’s speech was at once intriguing because of its content and dull because of the monotone in which it was delivered.


12) Noun Agreement

Nouns must agree in number when joined by a linking verb (usually to be or to become)

Hint: Look for the phrase "as a + profession" (actor, physicist, entomologist...)

Ex: Jenny and Robert want to become a scientist (scientists) when they grow up.

Ex: The Wikipedia has joined the Encyclopedia Britannica as favorite sources (as a favorite source) for research.


13) Relative Pronouns

Who/That vs. Which

Who is for people, which/that is for things. In Error-IDs, which is typically used incorrectly to refer to people; who is not used to refer to things.

Ex: Known for his many wives, King Henry VIII was a British monarch which (who/that) ruled during the Tudor period.

-When "which" appears by itself, it is usually incorrect; preposition + which (e.g. "in which") is usually correct.

-"Which" is always preceded by a comma; ‘That’ is never preceded by a comma

Correct: The movie that opened last Friday has earned rave reviews from critics.


Correct: The movie, which opened last Friday, has earned rave reviews from critics.

Very Important: Who vs. Whom is not actually tested on the SAT. "Who" is only switched with "which." If "whom" is underlined, ignore it.

Other Relative Pronouns

When is for Time

Where is for Places (It is incorrect to say, "The story where....")


14) Coordinating Conjunctions (and vs. but)

When conjunctions are underlined, make sure that they connect the two halves of the sentences logically. Ideas that are being continued need transitions like “and,” and ideas that are being contradicted need transitions like “but.”

Ex: People with a certain rare disease are unable to feel physical pain, and (but) this does not mean that they are unable to feel other kinds of pain.

Be on the lookout for "when," which is often used in place of "because" or "for."

Ex: It came as a surprise to no one that Santiago could not finish the race, when he had put little effort into training.


15) Redundancy (Rare, 1 per test maximum)

Ex: According to recent reports, the collapse of the country’s government is imminent and could occur in the future.


16) Usage (Rare, 1 per test maximum)

Ex: The tall buildings were just barely visual (visible) from the outskirts of the city.


Fixing Sentences

The following rules provide a general set of guidelines for the Fixing Sentences portion of the Writing section.

Rules for picking answers:

1) Shorter is better:

Always look at answers from shortest to longest

2) -ING (esp. Being) is BAD

Gerunds create sentence fragments

3) Passive Voice is BAD

-Active: I drink the water

-Passive: the water is drunk by me

The passive voice makes sentences wordy and awkward.

Major Concepts Tested

1. Concepts also tested on Error-Identification:

-Subject-Verb Agreement (Typically subject-prepositional-phrase verb)

-Antecedent Pronoun (Watch out for ItWhich, and This, which often lack antecedents)

-Verb Tense (esp. Tense Consistency)

-Conjunctions (and vs. but/however)

-Faulty Comparisons (always fix with that of/those of)

-Word Pairs (esp. between...and, so...that, just, not only...but also)

-Pronoun Case (he vs. him, rare) 


2. Sentence Fragments

1) Gerund replaces main verb

Incorrect: The book being banned from a number of schools because it was so controversial.

To fix the sentence, conjugate the verb:

Correct: The book was banned from a number of schools because it was so controversial.

2) Non-essential and subordinate clause errors 

Non-Essential: a verb should follow a non-essential clause

Incorrect: The book, which was banned from a number of schools, and it is extremely controversial.

Correct: The book, which was banned from a number of schools, is extremely controversial.

Subordinate: the main verb must appear in the same clause as the subject

Incorrect: The book, which was banned from a number of schools because it was so controversial.

Correct: The book was banned from a number of schools because it was so controversial.


Commas and Semicolons

Coordinating (aka FANBOYS) conjunction:

For, And, Nor, But, Or, Yet, So


Coordinating Conjunctions are used to join 2 complete sentences (independent clauses). They must ALWAYS be preceded by a comma:

Sentence 1: London is a very old city.

Sentence 2: It has many modern buildings.

Joined: London is a very old city, but it has many modern buildings.

If a comma alone is used to join two Independent Clauses, the result is what's known as a Comma Splice. Comma splices are always incorrect.

Comma Splice: London is a very old city, it has many modern buildings. 

Important: When two Independent Clauses that have the same subject are joined with a Coordinating Conjunction without repeating the second subject, no comma is necessary before the Coordinating Conjunction.

Correct: London is a very old city but has many modern buildings.

Incorrect: London is a very old city, but has many modern buildings.



Semicolon = Period. It is used to separate two complete sentences (independent clauses).

Correct: London is a very old city; it has many modern buildings.

There are five transitions (conjunctive adverbs) that should always be preceded by a semicolon when they appear at the beginning of a clause:

1) However

2) Therefore

3) Moreover

4) Consequently

5) Nevertheless


Correct: London is a very old city; however, it has many modern buildings.

But a semicolon should never precede a FANBOYS conjunction.

Incorrect: London is a very old city; but it has many modern buildings.


Note: when "however" is used parenthetically in the middle of a sentence, it must be surrounded by commas. Compare the following two sentences:

Correct: London is a very old city; it is, however, filled with modern buildings.

Correct: London is a very old city; however, it is filled with modern buildings.


In order to be successful on the Fixing Sentences section, you must be absolutely solid on the the four basic ways of combining independent clauses:

1) London is known for its gloomy weather, but it actually receives less rainfall than Paris does.

2) London is known for its gloomy weather; it actually receives less rainfall than Paris does.

3) London is known for its gloomy weather; however, it actually receives less rainfall than Paris does.

4) London is known for its gloomy weather but actually receives less rainfall than Paris does.


Dangling Modifiers

Rule: Always place modifiers as close as possible to the nouns they modify.

Incorrect: Having resigned for personal reasons, the ambassador's successor will probably be named tomorrow

Who resigned?

The ambassador. So "The ambassador" is the subject.

Therefore, the ambassador MUST be the first words after the comma

Correct: Having resigned for personal reasons, the ambassador plans to name his successor tomorrow


Misplaced Modifiers (Less Frequent)

Incorrect: John found his keys running down the street. (It sounds as if the keys are running along the street)

Correct: While running down the street, John found his keys.



Gerunds (the "-ing" form of a verb that acts a noun) are frequently wrong because they make sentences unnecessarily wordy and awkward. When used in place of of conjugated verbs, they also turn sentences into fragments. The easiest way to fix a gerund is to simply supply the subject and conjugate the verb.

Incorrect: The book was banned from a number of schools because of it being so controversial.

Correct: The book was banned from a number of schools because it was so controversial.

Important: The use of possessive vs. object pronouns before a gerund (e.g. because of his being vs. because of him being) is NOT tested on the SAT. The gerund construction itself is the issue, not the pronoun.


Non-Essential Clauses

The SAT will frequently include sentences with non-essential clauses placed in unexpected places -- if the sentence makes sense when the non-essential clause is removed, however, that answer will be correct. It does not matter that the placement of the clause may seem odd.

Correct: The author's latest novel is a gripping, if occasionally perplexing, piece of fiction.

Even if the original version of the sentence may sound strange, if we remove the non-essential clause, we are left with:

Correct: the author's latest novel is a gripping, if occasionally perplexing, piece of fiction.

Important: If a sentence contains a correctly used parenthetical clause and does not contain another grammatical error, it is virtually always correct, no matter how odd it may sound.



1. Lists (Easy)

The items in a list must all be in the same formate

Incorrect: I like biking, swimming, and to play soccer

Correct: I like biking, swimming, and playing soccer

2. "Phrase" or Two-Part Parallelism (Hard)

Frequently the last question of a section (#11 first section, #14 second)

Look for classic "noun + of + noun" structure

Incorrect: Jessye Norman is an American opera singer who is known for the emotional impact of her singing and her intellectual command of her music is impressive.

Correct: Jessye Norman is an American opera singer who is known for both the emotional impact of her singing and for her impressive intellectual command of her music.

Last modified on 14 January 2013
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