🎓 TinyProf's Comma Usage Guide

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1. What We're Solving

We need to figure out where commas belong (and where they don't) in complex sentences involving:

• Conditional clauses (like if/when phrases)
• Coordinating conjunctions (like and, but, or)
• Compound predicates (one subject doing multiple things)

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2. The Approach

Commas function as traffic signals — they tell readers when to pause and how parts of a sentence connect. The rules below will let you judge any sentence confidently.

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3. Step-by-Step Rules to Apply

🔑 Rule 1: Introductory Dependent Clauses → USE a comma

If a sentence starts with a dependent clause (often beginning with if, when, although, because, since), place a comma after it before the main clause.

> ✅ "If it rains tomorrow, we will cancel the picnic." > ❌ "If it rains tomorrow we will cancel the picnic."

Ask yourself: Does the sentence start with a subordinating word? Is the main idea still coming? → Comma needed!

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🔑 Rule 2: Dependent Clause AFTER Main Clause → Usually NO comma

When the dependent clause comes second, you generally skip the comma.

> ✅ "We will cancel the picnic if it rains tomorrow."

The logic: The sentence flows naturally without a pause signal when the main idea comes first.

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🔑 Rule 3: Two Independent Clauses with Coordinating Conjunction → USE a comma

When joining two complete sentences (each with its own subject + verb) using and, but, or, so, yet, for, nor, place a comma before the conjunction.

> ✅ "She studied hard, and she passed the exam."

Test: Can each part stand alone as a sentence? → Yes? Use the comma!

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🔑 Rule 4: Compound Predicate → NO comma

If one subject performs two actions connected by and, do not insert a comma.

> ✅ "She studied hard and passed the exam." > ❌ "She studied hard, and passed the exam."

The critical question: Is there a second subject after the conjunction? No subject = no comma!

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4. Applying the Rules — Your Checklist 📋

When you look at each highlighted position in your sentences, ask these questions in order:

| Question | If YES → | If NO → | |---|---|---| | Does the sentence START with a dependent clause? | ✅ Comma after it | Move to next question | | Are there TWO full sentences joined by and/but/or? | ✅ Comma before conjunction | Move to next question | | Is it one subject doing multiple things? | ❌ No comma | Re-examine the structure |

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5. Worked Mini-Examples

Sentence A: "When the bell rings[?] the students leave."

• Starts with when → dependent clause leads → ✅ Comma needed after rings

Sentence B: "The students leave[?] and walk home."

• Subject = The students, actions = leave AND walk → compound predicate, one subject → ❌ No comma

Sentence C: "The students leave[?] and their teacher locks the room."

• After and, we have a NEW subject (their teacher) → two independent clauses → ✅ Comma needed

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6. The Answer Framework

For each of your four sentences, apply this thinking script:

> 1. "Where does the dependent clause appear — beginning or end?" > 2. "After my conjunction, is there a new subject?" > 3. "Rule says... comma ✅ or no comma ❌"

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💡 Memory Tip

Try the "Two Fingers Test" for coordinating conjunctions:

• Point to the word before the conjunction → full sentence? ☝️
• Point to the word after the conjunction → full sentence? ✌️
• Two full sentences = comma! One lonely predicate = no comma! 🚫

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You're doing great tackling complex grammar — these rules become automatic with just a little practice! 🌟 Share your specific sentences and I'll walk through each one with you step by step!