What's in here. The eight parts of speech, sentence structure, subject-verb agreement, and the most-flagged common errors. Use it as a reference; you don't need to memorize it all at once.
Parts of speech
| Part | Job | Example |
|---|---|---|
| Noun | names a person, place, thing, or idea | dog, school, freedom, Toronto |
| Verb | action or state of being | run, is, jump, become |
| Adjective | describes a noun | red, tall, happy, three |
| Adverb | describes a verb, adjective, or other adverb | quickly, very, soon, here |
| Pronoun | replaces a noun | he, she, it, they, we, you |
| Preposition | shows position or relationship | in, on, under, with, before |
| Conjunction | joins words / clauses | and, but, or, because, although |
| Interjection | expresses emotion | wow!, ouch!, hey!, oh |
Tip: the same word can be different parts of speech in different sentences. "Run" is a verb in "I run fast" but a noun in "I went for a run".
Sentence structure
Subject + Predicate
Every complete sentence has a subject (who/what) and a predicate (the verb + the rest). The dog [subject] chased the ball into the yard [predicate].
Four sentence types by structure
- Simple: one independent clause. I ran.
- Compound: two independent clauses joined by a coordinating conjunction (FANBOYS) or semicolon. I ran, and she walked.
- Complex: one independent + one dependent clause. I ran because I was late.
- Compound-complex: two independents + at least one dependent. I ran because I was late, but she walked.
Four sentence types by purpose
- Declarative (statement, ends in .): She is here.
- Interrogative (question, ends in ?): Is she here?
- Imperative (command, ends in . or !): Come here.
- Exclamatory (strong emotion, ends in !): What a surprise!
Subject-verb agreement
Rule: singular subject takes singular verb. Plural subject takes plural verb. The dog runs. / The dogs run.
Tricky cases
- Compound subjects with "and" → plural verb. Sam and Lee are friends.
- Compound subjects with "or" / "nor" → verb agrees with the closest subject. Neither the boys nor the teacher knows the answer.
- Indefinite pronouns like everyone, somebody, anyone → singular. Everyone is here.
- Collective nouns like team, family, class → singular in North American English. The team is winning.
- Words between subject and verb don't change the agreement. The box of cookies is on the table. (box is singular; "of cookies" is just modifying)
10 most-flagged errors
- Run-on sentences. Two independent clauses smashed together with no punctuation. Fix with a period, semicolon, or coordinating conjunction.
- Comma splice. Two independent clauses joined by ONLY a comma. I ran, she walked. → I ran, and she walked.
- Fragment. Incomplete sentence (missing subject or verb). Walking to school. → I was walking to school.
- Their / there / they're. Their = possessive. There = a place. They're = they are.
- Your / you're. Your = possessive. You're = you are.
- Its / it's. Its = possessive (no apostrophe). It's = it is.
- Misplaced modifier. The describing word/phrase is too far from what it describes. I almost drove to the store. (didn't drive at all?) vs I drove to almost the store. (got close to it?)
- Subject-verb mismatch with "there is/are". There is many books. → There are many books.
- Pronoun reference unclear. When Tom saw Bill, he was happy. (Who's happy?) Fix: name the subject.
- Tense shifting mid-paragraph. Pick past or present and stick with it unless you have a reason to switch.