How is Conventions of Standard English tested on the ACT?

Questions ask you to fix punctuation, agreement, tense, and sentence structure. The ACT reuses a small set of rules — comma usage and subject-verb agreement chief among them — across every passage.

What's the most common mistake on ACT grammar questions?

Adding unnecessary commas, especially between a subject and its verb, and joining two complete sentences with a lone comma. Confusing its/it's and their/there/they're is another frequent slip.

What's the fastest way to improve at Conventions of Standard English?

When unsure about a comma, remember the ACT favors fewer, and test each side of a punctuation mark to see whether it's a complete sentence. Learn the four ways to fix a run-on and drill the possessive homophones.

ACT English · Conventions of Standard English

Conventions of Standard English

Conventions of Standard English is the grammar and punctuation core of the ACT English test: sentence structure, agreement, verb tense, pronouns, and especially comma usage. The ACT tests a compact set of rules repeatedly, so learning them pays off across every passage. Knowing when a clause is complete tells you what punctuation is allowed.

Quick answer

Conventions of Standard English is the grammar and punctuation core of the ACT English test — sentence structure, agreement, verb tense, pronouns, and especially comma usage — testing a compact set of rules repeatedly.

What it tests

Comma, semicolon, colon, and dash usage
Subject-verb and pronoun-antecedent agreement
Verb tense consistency and correct forms
Sentence structure: avoiding fragments, run-ons, and comma splices
Apostrophes for possession and contractions

Common mistakes

Adding unnecessary commas, especially between a subject and its verb
Using a comma to join two complete sentences (comma splice)
Confusing its/it's, their/there/they're, and whose/who's
Matching a verb to a nearby noun instead of the true subject

How to improve

When unsure about a comma, remember the ACT favors fewer, not more
Test each side of a punctuation mark to see whether it's a complete sentence
Drill the possessive/contraction homophones until they're automatic
Cross out interrupting phrases to find the real subject for agreement
Learn the four ways to fix a run-on: period, semicolon, comma plus conjunction, or subordination

Worked example

'The committee reviewed the proposal ___ it announced a decision the next week.' (A) , and (B) , (C) and (D) ; and

Both clauses are complete sentences, so a bare comma (B) is a splice and 'and' alone (C) creates a run-on. A comma plus the conjunction 'and' (A) correctly joins two independent clauses. '; and' is redundant since a semicolon already joins them.

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Related ACT English skills

Production of WritingProduction of Writing Knowledge of LanguageKnowledge of Language

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Frequently asked questions

How is Conventions of Standard English tested on the ACT?: Questions ask you to fix punctuation, agreement, tense, and sentence structure. The ACT reuses a small set of rules — comma usage and subject-verb agreement chief among them — across every passage.
What's the most common mistake on ACT grammar questions?: Adding unnecessary commas, especially between a subject and its verb, and joining two complete sentences with a lone comma. Confusing its/it's and their/there/they're is another frequent slip.
What's the fastest way to improve at Conventions of Standard English?: When unsure about a comma, remember the ACT favors fewer, and test each side of a punctuation mark to see whether it's a complete sentence. Learn the four ways to fix a run-on and drill the possessive homophones.