You read a student’s sentence and pause. The clauses fit together, and the grammar works, but the joining word doesn’t express what the student seems to mean. That’s the useful teaching moment: joining two complete clauses is only part of the decision. The writer also needs to choose the relationship between them.
This short Year 4 activity gives students a manageable way to compare and, but and so, explain their choices and try the same thinking in their own writing.
Decide what you want to say
Begin with three everyday questions:
- Am I adding information?
- Am I showing a contrast?
- Am I showing a result?
For the examples in this activity, and adds information, but highlights a contrast, and so presents the second idea as a result. Contrast doesn’t have to mean two literal opposites; it can also mark something unexpected. These meaning distinctions are described in the University of Newcastle’s sentence structure guide.
Try three sentence pairs
Tell students the intended relationship before they choose the joining word.
Add information
Mia packed the paint. Leo collected the brushes.
Joined: Mia packed the paint, and Leo collected the brushes.
Show a contrast
Mia wanted to paint outside. The rain kept everyone indoors.
Joined: Mia wanted to paint outside, but the rain kept everyone indoors.
Show a result
The paint spilled. Leo fetched a cloth.
Joined: The paint spilled, so Leo fetched a cloth.
In each example, ask students to point to the two clauses that could stand alone as sentences. Then ask what the conjunction tells the reader. This is the structure of a compound sentence described by the NSW Department of Education.
The examples model a comma before the conjunction when it joins the two independent clauses. Avoid turning that into a rule for every appearance of and, but or so: conjunctions can also connect individual words and phrases, as the Australian Government Style Manual explains.
Keep the clauses; change the link
Put these sentences side by side:
- The gate was locked, and we waited outside.
- The gate was locked, so we waited outside.
Ask, “Which version presents waiting as a result of the locked gate?” Then ask, “What does the other version leave the reader to infer?”
With and, the writer adds the second event. With so, the writer explicitly presents the waiting as a result. Both sentences can make sense in a suitable context, but they don’t say exactly the same thing. So communicates the relationship the writer proposes; it doesn’t prove that one event caused the other.
Make the joining word match the intention
Give partners the intention show a result, followed by this sentence: “The paper tore, but Ava fetched a new sheet.”
Ask them to change the conjunction and explain why. A clear revision is: “The paper tore, so Ava fetched a new sheet.” The first version isn’t ungrammatical; so simply matches the stated intention more closely. Invite students to invent a situation in which but would be reasonable, perhaps because Ava usually refuses to replace torn paper.
Listen for the reason behind the choice
Try a fresh pair: “Noah wanted to keep reading. The library was closing.” Ask students to join the clauses so that the sentence highlights a contrast. One likely response is: “Noah wanted to keep reading, but the library was closing.”
Next, ask them to complete “The library was closing, so …” with a complete clause describing a plausible response. For example: “The library was closing, so Noah borrowed the book.” Listen separately for a complete second clause, a sensible relationship and suitable punctuation. If an answer seems unclear, ask the student to explain the situation; a coherent context may support a choice you didn’t expect.
Use the same question in students’ writing
If students need support, rehearse the sentences aloud and begin with everyday language such as adding something, showing a difference and showing what happened as a result. This work can support Year 4 writing and editing of connected ideas, but it doesn’t cover the full complex-sentence requirement described in the Australian Curriculum Year 4 material.
At home, the same idea can become a quick oral conversation: say two short sentences, choose a joining word together, and discuss how a different choice changes the message.
For optional follow-up, the Conjunctions Year 4 Unit Plan extends the practice to identifying conjunctions, choosing them to match meaning, punctuating compound sentences, editing connections and writing purposeful sentences.
Finish by asking: “Choose one sentence in your writing. What relationship do you want the reader to notice? Read it again and check whether your conjunction makes that relationship clear.”