Year 5 · English · Language
Complex sentences
Combining a main clause with a subordinate clause using conjunctions such as 'because', 'although', 'when' and 'if'.
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Learning goals
Learners will
- Distinguish between main clauses and subordinate clauses.
- Use subordinating conjunctions to create complex sentences.
- Punctuate a complex sentence that begins with a subordinate clause.
Success looks like
- I can find the main clause and the subordinate clause in a sentence.
- I can join ideas with 'because', 'although', 'when', 'if' and 'unless'.
- I can use a comma when a sentence starts with a subordinate clause.
The big idea
A main clause makes sense on its own: 'We stayed inside.' A subordinate clause depends on a main clause to make full sense: 'because it was raining' leaves the reader waiting for more.
A complex sentence combines a main clause with a subordinate clause: 'We stayed inside because it was raining.'
Subordinate clauses usually begin with a subordinating conjunction. Each one shows a particular relationship:
- Cause: because, since
- Time: when, after, before, while, until
- Condition: if, unless
- Contrast: although, even though
The subordinate clause can come first or second. When it comes first, put a comma after it: 'Although she was tired, Emma finished the race.' When it comes second, a comma is usually not needed: 'Emma finished the race although she was tired.'
Worked examples
Identifying the clauses
Find the main and subordinate clauses: 'When the siren sounded, the swimmers left the water.'
- Find the subordinating conjunction: 'When'.
- The subordinate clause runs to the comma: 'When the siren sounded'.
- The rest makes sense alone: 'the swimmers left the water'. This is the main clause.
Answer: Main: 'the swimmers left the water'. Subordinate: 'When the siren sounded'.
Combining two sentences
Combine with a conjunction showing contrast: 'The track was steep.' 'We reached the top.'
- Choose a contrast conjunction: 'although'.
- Attach it to the clause that is the obstacle: 'Although the track was steep'.
- Put the subordinate clause first and add a comma.
Answer: Although the track was steep, we reached the top.
Fixing punctuation
Add the missing comma: 'If it rains tomorrow we will go to the museum.'
- Find the subordinate clause: 'If it rains tomorrow'.
- It comes first, so put a comma after it.
Answer: If it rains tomorrow, we will go to the museum.
Practice check
Have a go, then check your answers. Each answer comes with an explanation.
Answer guide for parents
Which is a subordinate clause?
because the dog was tired — 'Because the dog was tired' does not make complete sense on its own.
Which sentence is a complex sentence?
After I ate lunch, I read. — 'After I ate lunch' is a subordinate clause attached to the main clause 'I read'.
Which conjunction shows a condition?
unless — 'Unless' sets a condition: 'We will be late unless we hurry.'
Which sentence is punctuated correctly?
Before we left, we locked the door. — The subordinate clause comes first, so a comma follows it.
In 'Lena smiled because she had won', what is the main clause?
Lena smiled — 'Lena smiled' makes sense on its own.
Type the subordinating conjunction in: 'We waited inside until the storm passed.'
until — 'Until' begins the subordinate clause 'until the storm passed'.
Type the conjunction that best shows contrast: '___ he practised every day, Kai still found the piece difficult.' (although / because / if)
although — Practising and still finding it difficult is a contrast, so 'although' fits.
After which word should a comma go? 'While Dad cooked dinner Maya set the table.' Type the word.
dinner — The subordinate clause 'While Dad cooked dinner' comes first, so a comma goes after 'dinner'.
Watch out for
- Writing a subordinate clause on its own as a sentence ('Because I was late.'). It needs a main clause to complete it.
- Thinking a comma is always needed in a complex sentence. It is needed mainly when the subordinate clause comes first.
- Confusing coordinating conjunctions (and, but, so) with subordinating conjunctions (because, although, when).
Tips for parents
- Ask your child to finish your subordinate clauses aloud: 'Although it was cold…'
- Highlight subordinate clauses in a paragraph of a novel you are reading together.
- When editing, look for places where two short sentences could become one complex sentence.
Go further
- Write a paragraph where each sentence starts with a different subordinating conjunction.
- Play 'conditions' at dinner: everyone makes an 'If…' sentence about the weekend.
- Rewrite a set of instructions so that each step uses 'when', 'after' or 'before'.