Grammar Essentials

Master the grammar rules that matter most for clear, correct writing.

Why Grammar Matters

Grammar is the structure that holds language together. Good grammar:

• Makes your meaning clear
• Makes you appear credible
• Prevents misunderstandings
• Shows respect for readers

Remember: Grammar serves clarity, not perfection. The goal is effective communication.

Subject-Verb Agreement

Basic Rule

Subjects and verbs must match in number (singular/plural).

Correct:

• The dog barks. (singular)
• The dogs bark. (plural)
• She writes. (singular)
• They write. (plural)

Common mistakes:

Tricky Cases

1. Phrases Between Subject and Verb

Ignore words between subject and verb.

Pattern: Subject + [prepositional phrase] + Verb

Correct:

• The box of chocolates is on the table.
• The keys to the car are missing.
• One of the students has finished.

Tip: Cover the middle phrase to check: "The box is" / "The keys are"

2. Compound Subjects

With "and": Use plural verb

• John and Mary are coming.

With "or" or "nor": Verb agrees with nearest subject

• Neither John nor Mary is coming.
• Neither the teacher nor the students are coming.

3. Indefinite Pronouns

Always singular: each, every, either, neither, one, someone, anyone, everyone, no one

• Everyone is here.
• Each of the books has a cover.

Always plural: both, few, many, several

• Both are correct.
• Many were present.

Depends on context: some, all, most, none

• Some of the pie is gone. (pie = singular)
• Some of the pies are gone. (pies = plural)

Verb Tenses

The Main Tenses

Common Tense Mistakes

1. Tense Shifting

Wrong: I walked to the store and buy bread. Right: I walked to the store and bought bread.

Wrong: She says she will come, but she never showed up. Right: She said she would come, but she never showed up.

2. Present Perfect vs. Past Simple

Present Perfect: Connection to now

• I have lived here for five years. (still living here)

Past Simple: Finished in the past

• I lived there for five years. (not living there anymore)

3. Using "Would" for Habitual Past

Correct: When I was young, I would play outside every day. Correct: When I was young, I played outside every day.

Wrong: When I was young, I would be happy. (not habitual) Right: When I was young, I was happy.

Pronouns

Pronoun-Antecedent Agreement

Pronouns must match their antecedents in number and gender.

Wrong: Each student must bring their book. Right: Each student must bring his or her book. Better: Students must bring their books. (make plural)

Wrong: The company announced their new policy. Right: The company announced its new policy.

Pronoun Case

Common mistakes:

Tip: Remove the other person to check.

• "Between you and I" → "Between I" ✗
• "Between you and me" → "Between me" ✓

Pronoun Reference

Pronouns must clearly refer to a specific noun.

Unclear: John told Mark that he was wrong.

• Who was wrong? John or Mark?

Clear: John admitted he was wrong when talking to Mark.

Unclear: I removed the books from the boxes and threw them away.

• What was thrown away? Books or boxes?

Clear: I removed the books from the boxes and threw the boxes away.

Modifiers

Misplaced Modifiers

Place modifiers near the words they modify.

Wrong: I nearly ate all the cookies.

• Suggests you almost ate but didn't.

Right: I ate nearly all the cookies.

• You ate most of them.

Wrong: She served coffee to the guests in paper cups.

• Were the guests in paper cups?

Right: She served coffee in paper cups to the guests.

Dangling Modifiers

Make sure modifiers have something to modify.

Wrong: Walking down the street, the trees were beautiful.

• Trees can't walk.

Right: Walking down the street, I saw beautiful trees.

Wrong: To improve writing, practice is necessary. Right: To improve writing, you must practice.

Comma Usage

When to Use Commas

1. Compound Sentences

Before coordinating conjunctions (and, but, or, nor, for, so, yet) joining independent clauses.

Correct: I wrote the draft, and she edited it.

No comma: I wrote the draft and edited it. (one subject)

2. After Introductory Elements

After introductory words, phrases, or clauses.

Correct:

• However, I disagree.
• In the morning, I write better.
• After finishing the draft, I took a break.

3. Lists (Serial Comma)

Between three or more items.

Correct: I need paper, pens, and pencils.

Note: The comma before "and" (Oxford comma) is optional but recommended for clarity.

Without Oxford comma:

I'd like to thank my parents, Oprah and God.

• Suggests parents are Oprah and God

With Oxford comma:

I'd like to thank my parents, Oprah, and God.

• Four separate entities

4. Non-Essential Information

Around information that can be removed.

Correct: My brother, who lives in Boston, is visiting.

• I have one brother; his location is extra info.

No commas: My brother who lives in Boston is visiting.

• I have multiple brothers; specifying which one.

5. Direct Address

When addressing someone directly.

Correct: Thanks, John, for your help.

Meaning changes without commas:

• "Let's eat, Grandma!" (addressing Grandma)
• "Let's eat Grandma!" (cannibalism)

When NOT to Use Commas

Don't separate subject and verb:

• Wrong: The book I read yesterday, was excellent.
• Right: The book I read yesterday was excellent.

Don't separate verb and object:

• Wrong: She quickly wrote, the report.
• Right: She quickly wrote the report.

Apostrophes

Possessives

Singular Nouns

Add 's

Correct:

• the dog's bone
• James's book (or James' book, both acceptable)
• the boss's office

Plural Nouns Ending in S

Add only '

Correct:

• the dogs' bones
• the students' books
• the teachers' lounge

Plural Nouns Not Ending in S

Add 's

Correct:

• the children's toys
• the women's rights
• the people's choice

Contractions

Apostrophes show missing letters.

Common Apostrophe Errors

Key distinction:

• it's = it is
• its = belonging to it

Commonly Confused Words

Homophones (Sound Alike)

Other Common Confusions

Sentence Fragments

What Is a Fragment?

An incomplete sentence missing subject, verb, or complete thought.

Fragments:

• Because I was tired.
• Running down the street.
• A beautiful day.

Complete sentences:

• I left early because I was tired.
• I saw him running down the street.
• It was a beautiful day.

When Fragments Are Acceptable

In informal writing for emphasis or style:

• Question? Answer.
• Can't find words? Try these strategies.
• Absolutely not.

Run-on Sentences

Two Types

1. Fused Sentence

Two sentences joined with no punctuation.

Wrong: I love writing it helps me think.

Fixes:

• Period: I love writing. It helps me think.
• Semicolon: I love writing; it helps me think.
• Comma + conjunction: I love writing, and it helps me think.

2. Comma Splice

Two sentences joined with only a comma.

Wrong: I love writing, it helps me think.

Same fixes as above.

Parallel Structure

Keep similar elements in the same grammatical form.

Wrong: I like writing, to read, and running. Right: I like writing, reading, and running.

Wrong: She is smart, funny, and has talent. Right: She is smart, funny, and talented.

Wrong: The job requires attention to detail, working independently, and you must meet deadlines. Right: The job requires attention to detail, independent work, and meeting deadlines.

Active vs. Passive Voice

Active Voice (Preferred)

Subject performs action.

Structure: [Subject] [verb] [object] Example: The dog chased the cat.

Passive Voice

Subject receives action.

Structure: [Subject] [be verb] [past participle] (by [agent]) Example: The cat was chased by the dog.

When to Use Passive

1. Unknown actor: The window was broken.
2. Unimportant actor: Mistakes were made.
3. Focus on receiver: The president was elected.

Grammar-Checking Tools

Online Tools

• Grammarly: general checking
• Hemingway Editor: readability and simplicity
• ProWritingAid: style and grammar
• LanguageTool: open-source checker

Built-in Tools

• Microsoft Word: grammar and spell check
• Google Docs: basic grammar checking

Remember: Tools help but aren't perfect. Learn the rules yourself.

Practice Exercises

Exercise 1: Subject-Verb Agreement

Choose the correct verb:

1. The collection of books (is/are) impressive.
2. Either the teacher or the students (has/have) the key.
3. Everyone (need/needs) help sometimes.

Answers: 1. is, 2. have, 3. needs

Exercise 2: Fix Comma Errors

Add or remove commas:

1. After eating the dog went outside.
2. I need milk eggs and bread.
3. My friend who lives nearby is visiting.

Answers:

1. After eating, the dog went outside.
2. I need milk, eggs, and bread.
3. No change (if specifying which friend) OR My friend, who lives nearby, is visiting. (if I have one friend)

Exercise 3: Fix Pronoun Errors

Correct the pronouns:

1. Between you and I, this is difficult.
2. Each student must bring their book.
3. Me and John went to the store.

Answers:

1. Between you and me
2. Each student must bring his or her book (or make plural: Students must bring their books)
3. John and I went to the store

Summary

Essential grammar rules:

• Subject-verb agreement (singular with singular, plural with plural)
• Consistent verb tenses (don't shift unnecessarily)
• Correct pronoun case (I vs. me, she vs. her)
• Proper comma usage (compound sentences, introductory elements, lists)
• Apostrophes for possession and contractions
• Avoid fragments and run-ons
• Use parallel structure

Remember:

• Grammar serves clarity
• Learn rules, but tools help too
• Some rules are flexible in informal writing
• When in doubt, rewrite the sentence

Next: 06-style-tone.md. Develop your voice and match your tone to your audience.