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Duke University
Duke University
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Unweighted GPA: 3.7
SAT: 720 math
| 800 verbal


Low accuracy (4 of 18 factors)

3 Grammar Rules Every Student Messes Up On the ACT

The English portion of the ACT exam is 45 minutes long and consists of 75 questions, the bulk of which involve correcting grammatical errors found in the passages provided. Although intimidating at first glance, these grammar questions can usually be solved with knowledge of some basic grammar rules.

Below are the three most easily-overlooked problems on the ACT — not only are these the trickiest to spot, but they are also the most commonly-asked questions on the English section. Any student who has mastered these rules should see an immediate boost in their English scores.

1. Subject-verb agreement

The idea of subject-verb agreement is simple enough to understand — singular subjects require verbs with singular endings, while plural subjects go with plural verbs. Typically, singular verbs end with an “s”, while plural verbs do not.

However, the ACT can deliberately trick students with complicated sentences, separating subjects from their verbs or making a singular group appear plural in nature.

Example: Even the valedictorian, along with the rest of her classmates, were not immune to senioritis.

Revised: Even the valedictorian, along with the rest of her classmates, was not immune to senioritis.

Note: at first glance, the verb “were” seems like it should agree with “classmates,” which occurs right next to it. However, the true subject of the verb, “valedictorian,” is singular.

Example: The group of students expectantly stand in a circle around the teacher.

Revised: The group of students expectantly stands in a circle around the teacher.

Note: although multiple students are standing, the verb is singular because it refers to the single “group” that is the subject of the sentence.

2. Comma usage

In the multiple choice questions, the ACT often lists options with commas everywhere, inserting them into random places. Many of these options will intuitively “feel wrong” to students — however, to truly understand what is wrong with most of these choices, students must have a firm grasp on the concepts of phrases and clauses.

As a general overview, students should understand that phrases are typically separated from the rest of the sentence by commas and occur right next to whatever they are describing.

Example: The dog chased after the cat, barking and wagging its tail.

Revised: Barking and wagging its tail, the dog chased after the cat.

Note: we understand that it is the dog that is barking and wagging its tail, and so the phrase needs to be placed next to what it is describing.

Additionally, students need to recognize the difference between independent and dependent clauses, as well as how they differ in the way they appear in compound sentences.

Example: They stumbled their way through the dark forest, no one wanted to admit they were lost.

Revised: They stumbled their way through the dark forest; no one wanted to admit they were lost.

Note: the difference is subtle, but both halves of this sentence are independent clauses, and independent clauses cannot be separated by only a comma. For this sentence to be grammatically correct, the clauses must be separated either by a semicolon, as shown above, or by a comma and a coordinating conjunction, such as “and” or “but”.

3. Parallel structure

Verbs in all their forms can be confusing. The average high school student is usually aware of little beyond the various tenses: present, imperfect, past, future, etc., while a particularly grammar-savvy student might even know about gerunds, infinitives, and participles.

To simplify the possible forms that could occur on the English section, the ACT often employs parallel structure in its sentences. This is a simple enough concept on its own, where compound sentences or lists follow similar grammatical structures.

Example: After sleeping through my alarm, missing my bus, and I spilled my coffee, I finally stumbled into the office.

Revised: After sleeping through my alarm, missing my bus, and spilling my coffee, I finally stumbled into the office.

Note: the parallel structure here consists of the subject “[verb]-ing my [noun]”. While there are many different grammatically-correct ways to rewrite this sentence, the ACT will often limit your choices so that the only one you can make on the test will be the one that makes the sentence parallel.

To tackle the grammar questions on the ACT English section, there is no substitute for thorough knowledge of English grammar. Though such mastery is a daunting task, students will find that simply understanding the three concepts above in full will send them well on their way towards conquering this part of the exam.


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Angela Yang
ACT Verbal Division Manager

Short Bio
Angela is a student at Cornell College of Engineering. She enjoys teaching a variety of subjects and helping students realize their dreams.