ACT English: Mastering the Conventions of Standard English

Independent clause

A group of words with a subject and a verb that can stand alone as a complete sentence.

Dependent clause

A group of words with a subject and a verb that cannot stand alone and must be attached to an independent clause.

Run-on sentence

An error in which two independent clauses are joined without correct punctuation or a proper connector.

Comma splice

A specific type of run-on sentence in which two independent clauses are joined by only a comma.

Sentence fragment

A group of words punctuated like a sentence but missing a subject, a main verb, or a complete independent clause.

Parallel structure

The use of matching grammatical forms for ideas that play the same role in a sentence, such as items in a list or paired ideas.

Coordination

The linking of ideas of equal importance, often with a coordinating conjunction or a semicolon.

Subordination

The joining of ideas so that one idea depends on the other, often to show cause, contrast, time, or condition.

Coordinating conjunctions

The FANBOYS words—for, and, nor, but, or, yet, so—which join two independent clauses when used with a comma.

Subordinating conjunctions

Words such as because, although, when, since, if, and while that introduce dependent clauses.

Comma

A punctuation mark used for lists, introductory elements, nonessential information, and before a coordinating conjunction joining two independent clauses.

Semicolon

A punctuation mark used to join two closely related independent clauses without a conjunction or to separate complex list items.

Colon

A punctuation mark that introduces an explanation, example, or specification and must follow a complete sentence.

Apostrophe

A mark used mainly to show possession and to form certain contractions.

Em dash

A punctuation mark used to create a strong break or set off an interruption; an inserted aside usually needs two dashes unless the sentence ends there.

Parentheses

Punctuation marks used to enclose extra information that feels more separate from the main sentence.

Subject-verb agreement

The rule that a singular subject takes a singular verb and a plural subject takes a plural verb.

Pronoun-antecedent agreement

The rule that a pronoun must match the noun it refers to in number and usually in person.

Pronoun case

The form a pronoun takes based on its role in the sentence, such as subjective, objective, or possessive.

Pronoun reference

The clarity with which a pronoun points to one specific antecedent rather than to something vague or ambiguous.

Verb tense consistency

Keeping verb tenses aligned with the passage's time frame unless a logical reason requires a shift.

Adjective

A word that describes a noun.

Adverb

A word that describes a verb, an adjective, or another adverb; after a linking verb, an adjective is usually needed instead.

Modifier placement

The principle that a descriptive word or phrase should be placed next to the word it logically modifies to avoid misplaced or dangling modifiers.

Idiomatic expression

A standard English word pairing or phrase, often involving a preposition, such as 'responsible for' or 'prefer X to Y.'