Year 4 · English · Language
Compound sentences
Joining two main clauses with coordinating conjunctions such as 'and', 'but', 'or' and 'so' to show how ideas are related.
Awaiting educator review. This material was drafted by our content team with AI assistance and is waiting for review by a qualified educator. Please check it suits your child before using it. Created 10 October 2026.
These lessons were written around Australian Curriculum strands and matched to New Zealand year levels by age (NZ Year 1 is the first year of school). They are not yet mapped to The New Zealand Curriculum, so check them against your own learning programme.
Learning goals
Learners will
- Recognise a clause as a group of words built around a verb.
- Join two main clauses with a coordinating conjunction to form a compound sentence.
- Choose the conjunction that best shows the link between ideas.
Success looks like
- I can find the two clauses in a compound sentence.
- I can join two short sentences with 'and', 'but', 'or' or 'so'.
- I can explain why I chose my conjunction.
The big idea
A clause is a group of words built around a verb. 'The magpie swooped' is a clause; its verb is 'swooped'. A simple sentence has one clause.
A compound sentence joins two main clauses that could each stand alone. They are joined with a coordinating conjunction.
- and adds information: I fed the cat and Dad fed the dog.
- but shows a contrast: It was sunny but the wind was cold.
- or gives a choice: We can walk or we can ride our bikes.
- so shows a result: It started to rain so we went inside.
To check that a sentence is compound, cover the conjunction. If each side can stand alone as a sentence, it is compound. Writers often place a comma before 'but' and 'so', especially when the clauses are long.
Mixing simple and compound sentences makes writing smoother and more interesting than a string of short sentences.
Worked examples
Joining two sentences
Join: 'I wanted to swim.' 'The pool was closed.'
- Ask: how are the ideas related? The second idea is a contrast with the first.
- Choose 'but' for contrast.
- Remove the first full stop and lower-case the second capital: 'I wanted to swim, but the pool was closed.'
Answer: I wanted to swim, but the pool was closed.
Finding the clauses
Find the two clauses in: 'The baby was tired so she had a nap.'
- Find the conjunction: 'so'.
- Clause 1: 'The baby was tired' (verb: was).
- Clause 2: 'she had a nap' (verb: had).
- Each could stand alone, so this is a compound sentence.
Answer: 'The baby was tired' and 'she had a nap'.
Practice check
Have a go, then check your answers. Each answer comes with an explanation.
Answer guide for parents
Which sentence is a compound sentence?
The dog barked and the cat ran away. — It has two main clauses joined by 'and'.
Choose the best conjunction: 'I was hungry ___ I made a sandwich.'
so — Making a sandwich is the result of being hungry, so 'so' fits.
Choose the best conjunction: 'You can have an apple ___ you can have a pear.'
or — 'Or' gives a choice.
Which conjunction shows a contrast?
but — 'But' shows that the second idea is different from or unexpected after the first.
Which is a simple sentence?
Mia read a book. — 'Mia read a book.' has only one clause.
Type the conjunction in: 'The rain stopped and the sun came out.'
and — 'And' joins the two clauses.
Type the best conjunction to fill the gap: 'The road was icy ___ we drove slowly.'
so — Driving slowly is the result of the icy road.
How many main clauses are in: 'Sam likes cricket but Ella prefers netball.'? Type a number.
2 — 'Sam likes cricket' and 'Ella prefers netball' are two main clauses.
Watch out for
- Thinking any long sentence is compound. A compound sentence must have two clauses that could each stand alone.
- Overusing 'and' to join many ideas into one very long sentence. Encourage a mix of sentence lengths.
- Starting a new capital letter after the conjunction ('I ran but It rained'). The second clause continues the same sentence.
Tips for parents
- Say two short sentences aloud and ask your child to join them in as many ways as possible.
- Point out compound sentences in books you read together.
- Ask 'What is the link between these ideas?' to help your child choose the conjunction.
Go further
- Cut sentence strips in two and mix them up. Rejoin them with conjunction cards to make sensible (or silly) compound sentences.
- Rewrite a paragraph of very short sentences, joining some of them into compound sentences.
- Write a 'but' story where every sentence has a twist: 'I went to the beach, but…'