Most Important ACT English Grammar Rules


Most Important ACT English Grammar Rules

Most college-bound students are juggling so many competing priorities that they have limited time to prepare for the ACT. When planning your approach, it would be helpful to know what areas you should focus on to get the most point improvement in the shortest available time.

This article will discuss which grammar rules are most important to learn to make the greatest improvement in your ACT English score.


What Types of Questions are on ACT English?

Most Important ACT English Grammar Rules

ACT English is a passage based test. There are five passages and 75 questions. All passages have multiple paragraphs, and all questions are broken down into two broad categories: Usage and Mechanics and Rhetorical strategy.

Usage and Mechanics

Questions in this category test punctuation (both within and at the end of a sentence), grammar and usage (including, but not limited to subject-verb agreement, pronoun agreement, verb tense, pronoun case, different types of adjectives and adverbs, etc.), and sentence structure (including placement of modifiers and relationship between clauses). These questions make up approximately 55% of the ACT English test. *

Rhetorical Skills

Questions in this category ask about strategy (including understanding when to add or delete information from a passage), organization (including choosing the best introduction and/or concluding sentences, and transitions), and style (including choosing appropriate words, tone, diction, and avoiding redundancy and wordiness). These questions make up approximately 45% of the ACT English test. *

*Note: The ACT does not adhere to these guidelines strictly (sometimes Rhetorical skills questions make up more than 45% of the section), but generally these are good “guideline” percentages.

What Concepts are Tested on ACT English Section?

Most Important ACT English Grammar Rules

Most of the Grammar and Style rules that the ACT English section will test you on is almost as predictable as the type of the questions. Keep in mind that ACT heavily favors certain style and grammar rules, and completely ignores many others.

Why Should You Care?

What this means to you is that if you are aiming at a mid-range score, you should focus the bulk of your studying on the main grammar and style rules that are certain to be tested.

If you are targeting a high score, you should know all of the concepts listed here. ACT English section consists of 75 questions, so ignoring a few concepts that appear a low percentage of the time can hurt your score.

We’ve analyzed and categorized every question officially published by the ACT to come up with a list of most frequently tested concepts and the winners are …

Usage and Mechanics – Most Frequently Tested Concepts

Most Important ACT English Grammar Rules

The most frequently tested concept, making up 20.5% of the grammar questions, is the ability to correctly form and join sentences. These questions include understanding what a complete sentence is, including fragments and run-ons, as well as correct usage of semi-colons.

The second most-frequently tested concept, making up approximately 18% of the grammar questions, is correct use of commas, dashes, and colons.

In third and fourth places are correct usage of non-essential clauses and relative pronouns and correct verb tense and form making up 10.2 and 9.6% of the grammar questions respectively.

So, if you master just these four concepts, you will have enough information to answer approximately 60% of all grammar questions on the ACT English section.

Usage and Mechanics – Full Breakdown

If you are aiming at a high score, you must familiarize yourself with all of the concepts listed here.

#1. Correct sentence formation – 20.5% 

  • Recognizing fragments
  • Recognizing run-ons, including comma splices
  • Correctly joining sentences
  • Incorrectly used semi-colons

#2. Use of commas, dashes, and colons – 17.8%

  • No comma between subject and verb
  • No comma before and after a preposition
  • Comma usage when separating adjectives
  • No comma between adjective and the noun it describes
  • Comma usage :
    • after introductory words
    • between compound subjects or compound objects
    • around emphatic or reflexive pronouns
  • Usage of colons: for a list or explanation
  • Usage of dashes – with non-essential clauses, as intro to a list, or for a deliberate pause

#3. Correct formation of non-essential clauses and relative pronouns – 10.2%

  • Non-essential clause must be surrounded by commas
  • Correct usage of which vs. that; who vs. which; who vs. whom

#4. Verb tense and form – 9.6%

  • Correct usage of verb tense
  • Past tense vs. past participle
  • The need for “helping verb” when using past participle
  • Will vs. would
  • Gerund vs. infinitive

#5. Misplaced and dangling modifiers and word placement – 9.2%

  • Placement of descriptive phrases (hint: they must be next to the word they describe).
  • Placement of certain words to make the most sense within a sentence

#6. Correct usage of apostrophe – 7.5%

  • Formation of plural nouns
  • Singular vs. plural possession
  • Usage and meaning of common contractions (ex: it’s)

#7. Correct usage of pronouns – 7.5%

  • Pronoun agreement (consistent use)
  • Understanding an antecedent
  • Pronoun-antecedent agreement (with singular and plural pronouns)
  • Pronoun case

#8. Idioms – 5.1%

  • Correct idiomatic usage of prepositions

#9. Parallel Structure and Word Pairs – 4.1%

  • Use of matching prepositions
  • Matching items in a list
  • Neither …nor; either …or; not only…but also

#10. Subject-Verb agreement – 3.8%

  • Singular subjects – singular verbs
  • Plural subjects – plural verbs
  • Subject – non-essential clause – verb construction
  • Subject – prepositional phrase – verb construction
  • Verb before subject

#11. Adjectives vs. Adverbs – 2.4%

  • Adjectives are used to describe nouns
  • Adverbs are used to describe adjectives, verbs, and other adverbs
  • Correct usage of comparative and superlative forms (more vs. most)

#12. Comparative words – 2.4%

  • Correct usage of comparative words: more / less than; less vs. few; much vs. many

Rhetorical Strategy – Most Frequently Tested Concepts

Most Important ACT English Grammar Rules

These questions test your ability to make the paragraph or passage more logical and easier to read. Similar to usage and mechanics section, the ACT favors some rules over others. The most commonly tested rhetorical strategy questions are:

Logical transitions. This is not at all surprising since the whole point of these types of questions is to improve logic of the reading material. These questions are tested 18% of the time and test your ability to create logical connections within and between sentences and passages.

Adding or deleting information is the second most frequently tested concept, appearing 16.7% of questions. These questions test your understanding of the passage to determine relevance of information and whether it should be added or deleted. These questions also ask you to explain how the paragraphs or sentences are changed by the addition (or deletion) of information.

Two different categories: conciseness and replacing or rewording information appear third most frequently at 15.5% each. These questions test the students’ ability to recognize if the phrase in question is unnecessarily wordy, repetitive, redundant, or if the author is using circular language and replace it with a more streamlined (concise) choice. Passive vs. active voice is also tested here.

Rhetorical Strategy – Full Breakdown

If you are aiming at a high score, you must familiarize yourself with all of the concepts listed here.

#1. Logical transitions – 18.4%

  • Transitions within and between sentences and between paragraphs
  • Logically placed transition words (continuers, contradictors, etc)

#2. Adding information – 16.7%

  • Deciding if new information is relevant to the paragraph.
  • Understanding why it is relevant (or why not)

#3. Replacing or rewording information – 15.5%

  • Replacing a word or phrase to add emphasis to the passage
  • Rewording  irrelevant information

#4. Conciseness – 15.5%

  • Recognizing and removing repetitive words
  • Rephrasing wordiness
  • Replacing passive voice with active voice

#5. Deleting information – 11.7%

  • Deciding if information is relevant to the paragraph
  • How would deleting a word or phrase affect the paragraph?

#6. Diction – 8.4%

  • Commonly confused words: then/than; have/of

#7. Sentence Order / Placement and Paragraph Organization – 6.7%

  • Deciding if placement of a sentence makes contextual sense
  • Does one sentence or paragraph logically fit where it is?
  • Shift in topic between paragraphs

#8. Author’s Purpose / Goal – 5.4%

  • Recognizing main ideas in the passage
  • Recognizing specific and general ideas

#9. Formality – 1.5%

  • Determining if formality of the sentence matches the rest of the paragraph / passage

What Does a Test Look Like?

On average, an ACT English test would follow these approximate statistics:

8 questions on Forming Correct Sentences

7 questions on Commas, Dashes, and Colons

7 questions on Logical Transitions

6 questions on Adding Information

5 questions on Conciseness

4 questions on Verb Tense and Form

4 questions on Deleting Information

Non-Essential Clauses and Relative Pronouns – 4 questions

4 questions on Dangling and Misplaced Modifiers and Word Placement

3 questions on Diction

Apostrophe use – 3 questions

3 questions on Pronouns

2 questions on Idioms

2 questions on Parallel structure and Word Pairs

Sentence Order / Paragraph Organization – 2 questions

2 questions on Author’s Goal / Purpose

1 question on Subject-Verb Agreement

1 question on Adjectives vs. Adverbs

1 question on Comparison Words

1 question on Formality

75 questions in total.

You must keep in mind that this is a general guideline. Every test has some variation. For example, there could be 5 questions on Non-Essential Clauses and 0 question on Formality, etc.

How Should You Use This Information?

The most beneficial part of this information for you is that it can help guide your studying.

Here is an example of a study plan that can help you make the most of your available time and give you the best chance of improving your score.

  1. Take a REAL diagnostic test. Real tests, published by the ACT are the best because they will give you the most realistic questions. You can find officially published ACT tests here or you can get them by buying The Official ACT Prep Guide.
  2. After taking the diagnostic test, score it. This score is your benchmark. Make a list of every question you got wrong or guessed on (even if you guessed right) and determine what concept it is testing and why you got it wrong.

How Should You Use This Information? (cont’d)

  1. Compare your list of grammar errors with the list of question above. Which of your mistakes appears highest on the list?
  2. Focus your study time on the concepts that are highest on the list above. You should expect to get that type of question most frequently, so mastering the related grammar concept will give you the best chance to improve your score.
  3. When you feel confident that you have mastered the grammar concept that is highest on your list of mistakes, move on to the next one. Keep going down the list until you master all of them.

While implementing these steps, consider what your target ACT score is for the colleges and universities you are planning to apply to.

For example, if your goal is to improve from a score of 20 to a score of 24, then mastering the first 10-12 grammar concepts will help you achieve your goal and you don’t have to worry about every little question (especially the ones that may or may not be asked on your test day).

However, if you are aiming at a high, or even perfect score, you should pay attention to every grammar and rhetorical skill on the list. Missing just a few of these can hurt your chances of getting your goal score.

Next Steps

Before you start studying, read this article about 5 secrets to mastering the ACT English.

Now that you know exactly what is tested on ACT English, use the above knowledge to master each topic.

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