ACT English Parallel Structure: Write Balanced Sentences That Score

Parallel structure means that similar elements in a sentence should have the same grammatical form. Example of broken parallelism: "She likes reading, swimming, and to bike." The first two items are gerunds (reading, swimming), but the third is an infinitive (to bike). Fix: "She likes reading, swimming, and biking." All three are now gerunds. When elements in a list or comparison have the same form, they're parallel and the sentence sounds balanced. When they don't match, the sentence sounds awkward and is grammatically wrong.

Another example: "He was not only talented but also he was dedicated." The construction "not only...but also" requires parallel structure: "He was not only talented but also dedicated." Both phrases are now adjectives following "was," making them parallel.

Mistake 1: Mixing gerunds and infinitives in a list. "I want to run, jump, and swimming" should be "I want to run, jump, and swim" (all infinitives). Mistake 2: Breaking parallelism in "not only...but also" constructions. "She was not only smart but also she studied hard" should be "She was not only smart but also hardworking" or "She not only was smart but also studied hard." Mistake 3: Mismatching items in comparisons. "Singing is as enjoyable as to dance" should be "Singing is as enjoyable as dancing." The rule is simple: when items are listed together or compared, give them matching grammatical forms.

During practice, mark every list and comparison. Check that all items have the same form. This habit prevents parallelism errors before you even see the answer choices.

Sentence 1: "The team is fast, strong, and with good coordination." Error: First two items are adjectives; third is a prepositional phrase. Fix: "The team is fast, strong, and well-coordinated." Sentence 2: "She enjoys reading books and to watch movies." Error: Mixed gerunds and infinitives. Fix: "She enjoys reading books and watching movies." Sentence 3: "He was tall, intelligent, and had great humor." Error: Mixed adjectives and a clause. Fix: "He was tall, intelligent, and humorous." Sentence 4: "Not only did she win the race, but also the award." Error: Mismatched clauses. Fix: "She not only won the race but also won the award" or "Not only did she win the race, but she also won the award." Sentence 5: "Working out and to eat healthy are important for fitness." Error: Mixed gerunds and infinitives. Fix: "Working out and eating healthy are important for fitness."

Now find five parallel structure questions from a practice test. Mark each list or comparison and verify all items have matching forms. By the fifth question, you'll spot parallelism errors automatically.

Parallel structure errors appear on most ACT English tests, usually in the form of list or comparison questions. Because the rule is learnable and the errors are consistent, this is a high-value skill. Mastering parallel structure picks up 1-2 points on the English section because the error is predictable and the fix is straightforward once you know what to look for.

Drill parallel structure for one week. On every practice test, mark all lists and comparisons and verify they're parallel. By test day, you should spot parallelism errors faster than you spot comma splices.