Grammar Foundations

What you'll learn

• Identify nouns, verbs, adjectives, adverbs, pronouns, prepositions, conjunctions, and interjections
• Distinguish between independent and dependent clauses
• Recognize simple, compound, complex, and compound-complex sentences
• Understand how sentence structure errors appear on the ACT
• Identify the six main verb tenses (simple present/past/future and present/past/future perfect)
• Maintain consistent verb tense within a passage and recognize when tense shifts are intentional

Key concepts

Every English sentence contains at least a subject (noun or pronoun) and a predicate (verb). An independent clause expresses a complete thought and can stand alone; a dependent clause begins with a subordinating conjunction (because, although, when) or relative pronoun (who, which, that) and cannot stand alone. Verb tense is one of the most tested grammar concepts on the ACT (~10% of grammar questions). The six key tenses are: simple present ('she runs'), simple past ('she ran'), simple future ('she will run'), present perfect ('she has run'), past perfect ('she had run'), and future perfect ('she will have run'). The ACT tests whether you can maintain consistent tense within a paragraph and recognize when a shift is appropriate (e.g., a flashback requires past perfect). On the ACT, roughly 40% of English questions test conventions of standard English (grammar, usage, and mechanics), so understanding how words function in a sentence is essential for spotting errors quickly.

Pro tips

• When in doubt, find the main verb first, then find its subject. Many ACT traps separate the two with long phrases.
• Read each sentence in your head to hear whether it sounds complete; fragments and run-ons often 'feel' wrong even before you can name the rule.
• Keep a running list of grammar terms you are shaky on and review it before each study session.