Compound Sentences

Two independent clauses joined correctly

Learn how to form, punctuate, and choose coordinators/semicolons to join ideas. Practice with activities and download a ready-to-print worksheet.

Lesson Objectives

Identify

Spot compound sentences vs simple/complex.

Join

Use FANBOYS or a semicolon to join clauses.

Punctuate

Place commas/semicolons correctly.

Fix

Repair run-ons and comma splices.

What is a Compound Sentence?

Two independent clauses (IC + IC) joined correctly

  • Each clause can stand alone: subject + predicate, complete thought.
  • Join with: comma + coordinator (FANBOYS), semicolon (;), or semicolon + conjunctive adverb + comma.
  • Do not use only a comma between ICs → comma splice.
FANBOYSI finished my homework, so I watched TV.
SemicolonThe sun set; the stars appeared.

Tip: Split at the joiner. If both sides are full sentences by themselves, it’s compound. If not, don’t use a comma + FANBOYS.

Coordinating Conjunctions (FANBOYS)

for

We left early, for the storm was coming.

and

She studied, and she passed.

nor

He didn’t call, nor did he text.

but

It was late, but we continued.

or

Hurry up, or we’ll miss the bus.

yet

It looked easy, yet it was tricky.

so

I was tired, so I rested.

Comma rule: Place a comma before the coordinator if both sides are independent clauses.

Note: If the right side is not a full clause (no subject), it’s a compound verb → don’t use a comma.

Semicolon Patterns

  • IC; IC
  • IC; conjunctive adverb, IC (however, therefore, moreover, meanwhile, otherwise, instead, consequently)
IC; ICThe rain stopped; we went outside.
IC; Adv, ICThe team was exhausted; however, they kept playing.

Tip: Use a semicolon when the ideas are closely related and you don’t need a coordinator.

Avoid: Don’t pair a semicolon with FANBOYS.

Tricky: Not Compound

  • Simple with compound verb/subject is still simple: “She sings and dances.”
  • Complex: has a dependent clause (because, although, if, when, since, after…).
  • Comma splice/run-on: incorrect joining → needs fix.
SimpleKen and Ana read and write.
ComplexWe stayed because it rained.

Diagnostic: Look for subordinators (because, although, if…). If present, you’re in complex sentence territory, not compound.

Common Errors

Comma Splice

WrongIt rained, we stayed.
FixIt rained, so we stayed.

Run-on

WrongI studied I passed.
FixI studied; I passed.

Fix menu: Period (IC. IC), semicolon (IC; IC), or comma + FANBOYS (IC, and IC).

Choosing the Right Coordinator

and / so

adds/continues; cause → effect

He studied, and he reviewed. He was tired, so he slept.

but / yet

contrast; mild vs surprising

It was late, but we stayed; It looked easy, yet it was hard.

or / nor

choice; negative addition

Hurry now, or we’ll miss it. He didn’t call, nor did he text.

for

formal “because”

We left early, for the storm was coming.

Strategy: Decide the meaning first (add, contrast, choice, cause→effect) then pick the coordinator.

Examples

andAna cooked dinner, and Ken washed the dishes.
butIt looked expensive, but it was affordable.
orWe can walk, or we can take a jeepney.
yetThe road was rough, yet the ride was smooth.
soThe kids were hungry, so we ordered food.
semicolonThe sky darkened; thunder rumbled.

Tip: Vary your joiners to match meaning; don’t overuse “and.”

Punctuation in Compound Sentences

  • Comma before FANBOYS when both sides are independent clauses.
  • Semicolon for closely related ICs; no coordinator needed.
  • With conjunctive adverbs: IC; however, IC.

Quick check: Replace the comma with a period. If both sides work as sentences, your comma + FANBOYS is allowed.

Guided Practice

FixI studied, I passed. → I studied, so I passed.
ChooseWe can stay, ___ we can go. → or
PunctuateIt rained ___ we stayed. → , so

Practice: Choose the Best Answer

Question:

Loading…

Tip: Identify the relationship (add, contrast, choice, cause→effect) before picking punctuation.

Score: 0

Activity: Comma or Semicolon?

Choose the correct punctuation to join the clauses.

  • It was late __ we continued.
  • The rain stopped __ we went outside.
  • The team was exhausted __ however, they kept playing.

Tip: Read each side alone. If both are complete, prefer comma + FANBOYS (meaning-based) or a semicolon for tight connection.

Activity: Find the Coordinator

Click the coordinating conjunction in each sentence.

She studied , and she passed .

Hurry up , or we’ll miss the bus .

Activity: Build a Compound Sentence

Choose a left clause, a coordinator, and a right clause to form a correct compound sentence.

  • + +

Hint: Make sure both sides are clauses with subjects. If not, choose a different joiner or rewrite.

Quick Check

IdentifyCompound or not? “She sang and danced.” → Not compound (one clause)
IdentifyCompound? “She sang, and she danced.” → Compound

Practice Booster

Another round to reinforce.

Question:

Loading…
Score: 0

Assessment

How to take this: Choose the best answer for each question, then click Check Answers.

Loading questions…

Open Printable Worksheet

Test tip: Eliminate answers that create fragments or comma splices first, then choose the best meaning match.

Key Takeaways

Compound = IC + IC joined correctly.
Use comma + FANBOYS, or use a semicolon.
Conjunctive adverb pattern: IC; however, IC.
Avoid comma splices and run-ons.

Checklist: (1) Two clauses? (2) Correct joiner? (3) Correct comma/semicolon? (4) Meaning fits?

Nice Work!

You completed the Compound Sentences lesson

Press R to reset or F for fullscreen when presenting.

Next Steps

  • Retake the assessment
  • Fix comma splices in your writing
  • Write 5 compound sentences using different joiners