SAT and ACT Grammar and Punctuation Rules

Comprehensive vocabulary and rule definitions for SAT and ACT grammar, including punctuation, agreement, verb tenses, and modifier rules based on the provided guide.

Semicolon

A punctuation mark considered identical to a period on the SAT and ACT; it is used to separate two complete sentences or placed before conjunctive adverbs at the beginning of a clause.

Conjunctive Adverbs

Words such as however, therefore, or moreover that can follow a semicolon at the beginning of a clause to connect two complete sentences.

Colons and Single Dashes

Grammatically identical marks used to introduce lists and explanations; they must follow a full sentence but can be followed by either a full sentence or a fragment.

Comma + FANBOYS

A construction (comma followed by for, and, nor, but, or, yet, so) that is grammatically equivalent to a period or semicolon when connecting two independent clauses.

Comma Splice

A grammatical error where two complete sentences are joined by only a comma.

Dependent Clause

A fragment that cannot stand on its own as a complete sentence and begins with subordinating conjunctions such as although, because, when, until, while, or since.

Continuers

Transitions such as in addition, moreover, in fact, for example, and then that add similar ideas, emphasize previous ideas, or convey sequence.

Cause-and-effect Transitions

Words such as therefore, consequently, and thus that indicate an action or event is the result of a previous one.

Contradictors

Transitions such as however, nevertheless, and in contrast that signal opposing ideas.

Non-essential Information

A clause, phrase, or word that can be removed from a sentence without affecting its basic meaning; it can be punctuated with two commas, two dashes, or two parentheses.

Compound Items

Nouns, verbs, or adjectives linked by 'and' that should not be separated by a comma.

Apostrophe with Singular Nouns

Formed by adding 's to show possession (e.g., the cell's DNA).

Apostrophe with Plural Nouns

Formed by adding an apostrophe after the 's' for regular plurals (e.g., the cells' DNA) or 's for irregular plurals (e.g., the people's responses).

It’s vs. Its

It's means 'it is'; its is the possessive form of 'it'.

They’re vs. Their vs. There

They're means 'they are'; their is possessive; there refers to a place.

Who’s vs. Whose

Who's means 'who is'; whose is the possessive form of 'who' and can be used for people, things, or places.

Who(m) vs. Which

Who or whom is used for people, while which is used for things.

Who vs. Whom

Who is used before a verb; whom is used after a preposition.

Each and Every

Modifiers that make a subject grammatically singular, requiring a singular verb.

Collective Nouns

Nouns representing a group (e.g., group, country, school, team) that are considered grammatically singular.

Present Perfect Tense

Formed using has/have + verb to indicate an action that began in the past and continues into the present, often used with 'for' or 'since'.

Past Perfect Tense

Formed using had + verb to describe the earlier of two completed actions in the past; required when the phrase 'by the time' is used.

Passive Voice

A construction where the subject and object are flipped (e.g., y was done by x), often considered incorrect for being wordy or awkward, though sometimes grammatically necessary.

Dangling Modifier

An error where a descriptive phrase at the start of a sentence does not logically describe the noun placed immediately after the comma.

Faulty Comparison

An error occurring when equivalent items (people to people, things to things) are not compared, often corrected using 'that of' or 'those of'.

Quantity Words for Plural Nouns

Words including number, many, and fewer used for countable, plural items.

Quantity Words for Singular Nouns

Words including amount, much, and less used for uncountable, singular items.

Superlative

The form of an adjective (e.g., best, strongest, most interesting) used when comparing three or more items.