{"id":16908,"date":"2026-02-18T09:03:11","date_gmt":"2026-02-18T16:03:11","guid":{"rendered":"https:\/\/www.petersons.com\/blog\/?p=16908"},"modified":"2026-02-18T09:03:11","modified_gmt":"2026-02-18T16:03:11","slug":"act-grammar-rules-you-must-know-for-testing","status":"publish","type":"post","link":"https:\/\/www.petersons.com\/blog\/act-grammar-rules-you-must-know-for-testing\/","title":{"rendered":"ACT Grammar Rules You MUST Know for Testing"},"content":{"rendered":"<p><span style=\"font-weight: 400;\">The ACT English section has hidden patterns, and some of the most common mistakes\u2014comma splices, run-ons, and subject-verb agreement\u2014are exactly the ones you can master before test day. ACT points can be lost on these predictable grammar errors, and we want to help you secure all the points you can! In this post, we&#8217;ll break down the ACT grammar rules you must know to boost your score and move with clarity through the aggressive pace of the ACT English test.<\/span><\/p>\n<h2><b>What Is Tested on ACT English?\u00a0<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">There are two basic question types on the English test: Conventions of Standard English and Rhetorical Skills.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Conventions of Standard English questions assess:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Punctuation<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Grammar<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Sentence Structure<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Rhetorical Skills questions assess:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Style<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Organization<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Strategy<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Today, we will be focusing on grammar, as mastering ACT grammar rules will be an integral boost to your composite score.<\/span><\/p>\n<h2><b>Punctuation, Clause Structure, and Agreement ACT Grammar Rules<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">Dive into the technical must-knows with us in this section!<\/span><\/p>\n<h3><b>Comma Splices &amp; Corrections<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">One of the test\u2019s favorite ACT grammar questions asks how to connect independent clauses. To get started with accomplishing connecting independent clauses, let\u2019s review some sentence structures below:<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A <\/span><b>simple sentence<\/b><span style=\"font-weight: 400;\"> is made up of a single, independent clause.<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Simple sentences may contain compound subjects, compound predicates, and\/or lengthy subject and predicate modifiers, such as adjective and adverb phrases.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">A <\/span><b>compound sentence<\/b><span style=\"font-weight: 400;\"> is formed when two or more independent clauses are joined together.<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">A compound sentence requires punctuation and linking words to join the two independent clauses.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Two types of <\/span><b>linking words<\/b><span style=\"font-weight: 400;\"> are used to form compound sentences:<\/span><\/p>\n<ol>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Coordinating conjunctions. The seven coordinating conjunctions are For, And, Nor, But, Or, Yet, and So.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Conjunctive adverbs. Conjunctive adverbs express a particular relationship (such as contrast, sequence, or cause\/effect) between two ideas.<\/span><\/li>\n<\/ol>\n<p><span style=\"font-weight: 400;\">There are three correct ways to join independent clauses into a compound sentence:<\/span><\/p>\n<ol>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Comma + Coordinating Conjunction<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Semicolon<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Semicolon + Conjunctive Adverb + Comma<\/span><\/li>\n<\/ol>\n<h4><b>Here are examples in action:<\/b><\/h4>\n<p><b>The Incorrect Comma Splice<\/b><span style=\"font-weight: 400;\">: I studied all week, I passed the test.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A comma splice is not a correct sentence. To correct a comma splice, we can do a few things.\u00a0<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Correction 1 (Comma + Coordinating<\/b> <b>Conjunction)<\/b><span style=\"font-weight: 400;\">: I studied all week, so I passed the test.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Correction 2 (Semicolon)<\/b><span style=\"font-weight: 400;\">: I studied all week; I passed the test.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Correction 3 (Semicolon + Conjunctive Adverb + Comma)<\/b><span style=\"font-weight: 400;\">: I studied all week; therefore, I passed the test.<\/span><\/li>\n<\/ul>\n<h3><b>Punctuation Mastery<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Here are some specific grammar rules for the ACT regarding colons, dashes, and semicolons. Many ACT grammar questions focus on punctuation; knowing when to use a comma versus a semicolon is vital.<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Colons and semi-colons are used to combine independent clauses and offset or indicate lists and series.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Commas, dashes, and parentheses are used to offset or indicate nonrestrictive information. These clauses could contain extra details that could be removed without changing the core meaning of the sentence.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Restrictive clauses require no special punctuation as they contain essential details needed to identify the noun they modify.<\/span><\/li>\n<\/ul>\n<h4><b>Example of these grammar rules:<\/b><\/h4>\n<table>\n<tbody>\n<tr>\n<td><span style=\"font-weight: 400;\">Rule in Action<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Explanation<\/span><\/td>\n<\/tr>\n<tr>\n<td><b>Nonrestrictive (Needs Commas)<\/b><span style=\"font-weight: 400;\">: Sarah Miller, <\/span><b>a student from Chicago<\/b><span style=\"font-weight: 400;\">, scored a perfect 36 on the English section.<\/span><\/td>\n<td><span style=\"font-weight: 400;\">The clause &#8220;a student from Chicago&#8221; is extra information about Sarah Miller. If you remove it, the sentence still makes sense: Sarah Miller scored a perfect 36&#8230; Therefore, it is offset with commas.<\/span><\/td>\n<\/tr>\n<tr>\n<td><b>Restrictive (No Commas)<\/b><span style=\"font-weight: 400;\">: The student who scored a perfect score on the English section was offered a full scholarship.<\/span><\/td>\n<td><span style=\"font-weight: 400;\">The clause &#8220;who scored a perfect score on the English section&#8221; is essential to identify which student you are talking about. If you remove it, the meaning changes significantly. Therefore, no commas are used.<\/span><\/td>\n<\/tr>\n<tr>\n<td><b>Semicolon Usage<\/b><span style=\"font-weight: 400;\">: You must master these three rules before test day; <\/span><b>otherwise<\/b><span style=\"font-weight: 400;\">, your score will suffer due to predictable errors. (Semicolon + Conjunctive Adverb + Comma) I passed the practice test; <\/span><b>my confidence immediately improved<\/b><span style=\"font-weight: 400;\">. (Semicolon to join two closely related independent clauses)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Semicolons are used to connect two complete, independent sentences (clauses) that are closely related in meaning. They are a powerful tool to avoid comma splices and run-on sentences, as you covered earlier. <\/span><b>The semicolon replaces the period and makes a stronger connection between the two ideas.<\/b><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3><b>Run-on Sentences<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">A run-on sentence is two or more independent clauses joined <\/span><b>without<\/b><span style=\"font-weight: 400;\"> the right punctuation and\/or linking words.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">There are three ways to correct run-on sentences:<\/span><\/p>\n<ol>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Change one of the independent clauses into a dependent clause to form a complex sentence.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Separate the independent clauses to form two simple sentences.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Join the independent clauses with a comma and one of the FANBOYS (For, And, Nor, But, Or, Yet, So), a semi-colon, or a semi-colon and a conjunctive adverb.<\/span><\/li>\n<\/ol>\n<h4><b>For example:<\/b><\/h4>\n<p><b>The Incorrect Run-on Sentence<\/b><span style=\"font-weight: 400;\">: The ACT English test is fast it is important to practice your pacing before test day.<\/span><\/p>\n<p><b>Correction 1 (Complex Sentence)<\/b><span style=\"font-weight: 400;\">: Since the ACT English test is fast, it is important to practice your pacing before test day.<\/span><\/p>\n<h3><b>Subject-Verb Agreement<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">English grammar on the ACT loves to hide the subject behind long prepositional phrases, so it\u2019s very important to understand subject and verb agreement.<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Subject-verb agreement refers to using a verb form that matches or agrees in number with the subject.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">If a subject is singular, its verb must also be singular; if a subject is plural, its verb must also be plural.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Indefinite pronouns are pronouns that don&#8217;t have an obvious antecedent or might not refer to a particular noun. Special care must be taken to make sure that plural indefinite pronouns are paired with plural verbs and singular indefinite pronouns are paired with singular verbs.<\/span><\/li>\n<\/ul>\n<h4><b>For example:<\/b><\/h4>\n<p><b>Incorrect Subject-Verb Agreement<\/b><span style=\"font-weight: 400;\">: The <\/span><span style=\"font-weight: 400;\">list<\/span><span style=\"font-weight: 400;\"> of essential grammar rules <\/span><span style=\"font-weight: 400;\">are<\/span><span style=\"font-weight: 400;\"> very long.<\/span><\/p>\n<p><b>Correct Subject-Verb Agreement<\/b><span style=\"font-weight: 400;\">: The <\/span><span style=\"font-weight: 400;\">list<\/span><span style=\"font-weight: 400;\"> of essential grammar rules <\/span><span style=\"font-weight: 400;\">is<\/span><span style=\"font-weight: 400;\"> very long. (The subject is &#8220;list,&#8221; which is singular and requires the singular verb \u201cis\u201d).<\/span><\/p>\n<h2><b>Practice Makes Progress with ACT Grammar Rules<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">The secret to a high ACT English score isn&#8217;t memorizing obscure rules; it&#8217;s mastering high-frequency concepts. If you&#8217;re ready to move beyond just reading the rules and truly master sentence structure, punctuation, and agreement with hundreds of test-like examples, our <\/span><a href=\"https:\/\/www.petersons.com\/testprep\/act\/\"><span style=\"font-weight: 400;\">ACT course<\/span><\/a><span style=\"font-weight: 400;\"> is your next step. We break down complex concepts, such as the comma + coordinating conjunction and the independent\/dependent clause relationship, with easy-to-understand explanations and specific practice questions. Take many an <\/span><a href=\"https:\/\/www.petersons.com\/testprep\/act\/\"><span style=\"font-weight: 400;\">ACT English practice test<\/span><\/a><span style=\"font-weight: 400;\"> with us and walk into the exam with high-score-earning confidence.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The ACT English section has hidden patterns, and some of the most common mistakes\u2014comma splices, run-ons, and subject-verb agreement\u2014are exactly the ones you can master before test day. ACT points can be lost on these predictable grammar errors, and we want to help you secure all the points you can! In this post, we&#8217;ll break<\/p>\n","protected":false},"author":53,"featured_media":16909,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"categories":[3,6],"tags":[16,8548,6342,1170,557],"class_list":{"0":"post-16908","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-colleges","8":"category-test-prep","9":"tag-act","10":"tag-act-english","11":"tag-act-score","12":"tag-act-scores","13":"tag-grammar"},"better_featured_image":{"id":16909,"alt_text":"ACT grammar rules imagery with hand writing on paper and editing marks.","caption":"Document review collage element, sticker, clip art. Halftone hand making grammar, spelling check, searching for mistakes, proofreading paper. 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Halftone hand making grammar, spelling check, searching for mistakes, proofreading paper. Modern retro vector illustration on transparent background","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"Document review halftone collage vector illustration","orientation":"0","keywords":["review","information","check","revision","mark"]}},"post":16908,"source_url":"https:\/\/wp-media.petersons.com\/blog\/wp-content\/uploads\/2026\/02\/13142554\/Grammar-ACT.jpg"},"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.2 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>ACT Grammar Rules You MUST Know for Testing - Peterson&#039;s<\/title>\n<meta name=\"description\" content=\"Learn the essential ACT grammar rules you MUST know for testing. 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