ACT English: Parallel Structure in Coordinate Pairs and Series

Parallel structure means matching grammatical forms when you list items or pair them with conjunctions. Faulty: "I like reading, writing, and to paint." Correct: "I like reading, writing, and painting." (All gerunds.) The rule: Items joined by and, or, nor, but should have the same grammatical form. Example faulty pairs: "She is intelligent and works hard" (adjective + verb phrase). Correct: "She is intelligent and hardworking" (both adjectives) or "She is smart and works hard" (both verbs). On the ACT, parallel structure errors are among the most common and test grammatical awareness. When you see "and," "or," "but," or "nor," check that the items on both sides match grammatically.

Why it matters: Parallel structure is about clarity and rhythm. "I went to the store, the mall, and I ate lunch" is awkward. "I went to the store, the mall, and the restaurant" is smooth. Graders reward parallel structure because it signals careful, polished writing.

Error 1: Mixing nouns and verb phrases. "She enjoys swimming and to hike." Fix: "She enjoys swimming and hiking" (both gerunds). Error 2: Mixing adjectives and nouns in a list. "The car is fast, red, and reliable" (good). "The car is fast, red, and a bargain" (bad—bargain is a noun). Error 3: Mixing prepositional phrases and clauses. "She wrote the essay on Thursday and after reviewing it twice." Fix: "She wrote the essay on Thursday and reviewed it twice" (both verb phrases). Error 4: Inconsistent parallelism in a series of three or more items. "He wanted to succeed, earn respect, and being happy." Fix: "He wanted to succeed, earn respect, and be happy" (all infinitives). The fix is always: Identify the first item's grammatical form, then match all others to it.

Checklist: (1) Find the conjunction (and, or, but, nor). (2) Identify the first item's form (noun, verb, adjective, phrase, clause). (3) Check the second (and third) item's form. (4) If they don't match, rewrite to match. (5) Read aloud to verify it sounds right.

1. "She likes to swim and jogging." Fix: "She likes to swim and jog" or "She likes swimming and jogging." 2. "The book is long, detailed, and was expensive." Fix: "The book is long, detailed, and expensive." 3. "He ran quickly and with determination." Fix: "He ran quickly and determinedly" or "He ran with speed and determination." 4. "She studied hard, attended every class, and did the homework." (Already correct—all past tense verbs.) 5. "They wanted to win the game, earn a trophy, and being respected." Fix: "They wanted to win the game, earn a trophy, and be respected." For each, identify the first item's form, then rewrite to match all items to that form.

Daily drill: Write ten sentences with lists or pairs. Intentionally create parallel structure errors. Then fix each one. Notice patterns: most errors mix gerunds with infinitives or adjectives with nouns.

Parallel structure errors appear in 2-3 questions per ACT English section. These are entirely preventable if you know the rule and apply a simple checklist. Each question is worth 1 point, and catching parallel errors signals grammatical sophistication. This skill alone can gain you 2-3 points per test (10-15 overall) because the rule is straightforward and errors are consistent and recognizable.

Spend 1-2 days on parallel structure. Practice identifying the grammatical form of the first item and matching all others. By test day, spotting parallel structure errors will be automatic.