B. Foundations of Language · Spelling, Grammar and Punctuation

Compound-Complex Sentences

B3.1 B3.3About 45 minutes

Learning goals

I can identify simple, compound, complex and compound-complex sentences.
I can build a compound-complex sentence with two independent clauses and at least one dependent clause.
I can punctuate compound-complex sentences with commas in the right places.
I can use linking words and phrases to connect ideas between sentences.

Words to know

clause
A group of words with a subject and a verb.

independent clause
A clause that makes sense by itself as a sentence.

dependent clause
A clause that starts with a word like because, when, if or although and can't stand alone.

coordinating conjunction
A joining word that links two equal parts: for, and, nor, but, or, yet, so (FANBOYS).

subordinating conjunction
A word that starts a dependent clause: because, when, if, although, after, before, since, while, until, unless.

compound-complex sentence
A sentence with at least two independent clauses and at least one dependent clause.

cohesive ties
Words and phrases that link ideas together, like however, as a result, meanwhile and pronouns.

Remember from Grade 4

In Grade 4 you learned about clauses (a subject + a verb) and phrases (no subject-verb pair). You built three kinds of sentences:

Simple: one independent clause. The snow fell.
Compound: two independent clauses joined with a comma and a joining word. The snow fell, and the wind blew.
Complex: an independent clause + a dependent clause. Because the snow fell, school was closed.

In Grade 5 you'll learn the fourth kind, the compound-complex sentence. It's like a combo meal: compound and complex at the same time!

What is a compound-complex sentence?

A compound-complex sentence has:

at least two independent clauses (the compound part), and
at least one dependent clause (the complex part).

When the bell rang, we lined up at the door, and our teacher counted us.

When the bell rang → dependent clause (starts with when)
we lined up at the door → independent clause
our teacher counted us → independent clause, joined with , and

A compound-complex sentence: one dependent clause and two independent clauses joined with and.

Sentence type	Independent clauses	Dependent clauses	Example
Simple	1	0	The loons called.
Compound	2 or more	0	The loons called, and the fish jumped.
Complex	1	1 or more	The loons called while the sun set.
Compound-complex	2 or more	1 or more	The loons called while the sun set, and the fish jumped.

Count the clauses to name the sentence type

Count the clauses to name the sentence type. A compound-complex sentence sits in the corner with 2 or more independent clauses and at least one dependent clause.

Punctuating compound-complex sentences

Put a comma before the coordinating conjunction (FANBOYS) that joins the two independent clauses: ..., and ... / ..., but ... / ..., so ...
If the dependent clause comes first, put a comma after it: Although it was cold, ...
If the dependent clause comes at the end of a clause, you usually don't need a comma before it: ... the fish jumped while the sun set.

Worked example

Let's build one

Combine these three ideas into one compound-complex sentence: It snowed all night. / School was cancelled. / We built a snow fort.

Pick one idea to be the dependent clause. Add a subordinating conjunction: Because it snowed all night.
The other two ideas are independent clauses: school was cancelled and we built a snow fort.
Join the two independent clauses with a comma and a FANBOYS word: school was cancelled, so we built a snow fort.
Put the dependent clause first, with a comma after it.

Because it snowed all night, school was cancelled, so we built a snow fort.

Worked example

Let's identify the type

What type is this sentence? My grandmother taught me to make bannock, and I make it every Sunday when my cousins visit.

Find each subject + verb. grandmother taught → independent clause.
I make → independent clause, joined by , and.
when my cousins visit → starts with when, so it's a dependent clause.
2 independent + 1 dependent.

Compound-complex.

Just for fun

Because this joke was getting long, I added a comma, and now it's a compound-complex sentence. (Check it: one dependent clause, two independent clauses!)

Linking ideas between sentences

Good writers also connect ideas from one sentence to the next. These links are called cohesive ties. They help readers follow your thinking:

Time: first, next, meanwhile, afterward, finally
Adding: also, in addition, furthermore
Contrast: however, on the other hand, instead
Cause and effect: as a result, therefore, because of this
Pronouns that point back: The moose crossed the road. It stopped to look at us.

A linking word at the start of a sentence is usually followed by a comma: However, the lake was still frozen.

However needs a period before it

Don't join two sentences with only a comma before however. Not correct: It was sunny, however it was cold. Use a period (or a semicolon): It was sunny. However, it was cold.

Hands-on activity

Sentence-building cards

You need: three colours of paper (or three different symbols on white paper), scissors (ask a grown-up), and a pencil.

On the first colour, write 5 short independent clauses (the dog barked, we ate supper).
On the second colour, write 5 dependent clauses (because the doorbell rang, after we got home).
On the third colour, write the joining words and, but, so, or, yet.
Mix and match to build compound-complex sentences. Each one needs 2 independent cards, 1 dependent card and 1 joining word.
Write your three funniest or best sentences, with commas in the right places, and read them aloud.

Your turn

What two things does a compound-complex sentence need?

Name the type: The ice cracked.

Name the type: The ice cracked, so we stayed off the pond.

Name the type: Although the sun was out, the ice cracked, so we stayed off the pond.

Add the missing commas: When we got to the cabin Dad lit the fire and I unpacked the food.

Underline the dependent clause: I wanted to go skating, but the rink closed because the ice was melting.

Add a linking word to connect these sentences: We practised every day. We won the tournament.

More practice: warm-up

What do the letters FANBOYS stand for?

Is because it rained an independent or dependent clause?

Is the dog wagged its tail an independent or dependent clause?

Name the type: We ate pancakes because it was Saturday.

Where does the comma go? I like soup but my sister likes salad.

More practice: on your own

Combine into one compound-complex sentence: The power went out. / We lit candles. / We played cards.

Is this compound-complex? After the game, we went home and ate supper. Explain.

Add the missing commas: If it snows tomorrow we will go sledding but we must be home by four.

Name each clause in: Mia read the book, but Leo watched the movie because he had a cold.

Choose a linking word: Ontario has many lakes. ______, it borders four of the Great Lakes.

Challenge

Write a compound-complex sentence about a Canadian holiday. Label the clauses.

Fix this run-on and make it compound-complex: the wind howled the trees bent we stayed inside

Rewrite with a cohesive tie that shows contrast: Many people think beavers eat fish. Beavers eat plants, like bark and leaves.

Check your understanding

Quiz

A compound-complex sentence has...

Which sentence is compound-complex?

Which is a dependent clause?

Which sentence is punctuated correctly?

Which linking phrase shows cause and effect?

What type is We stayed home because I was sick?

For parents and teachers

Big idea (B3.1, B3.3): In Grade 5, students identify and construct various sentence types, including compound-complex sentences, and use commas correctly within them. The B3 overall expectation also mentions cohesive ties, the linking words that connect sentences into a paragraph.

How to help at home:

When reading together, find a long sentence and ask: "How many clauses? Which one could stand alone?"
In your child's writing, look for many short sentences in a row, and help combine two or three into one.
Encourage linking words between sentences, but in moderation.

Common difficulties:

Mistaking phrases for dependent clauses (After the game vs After we played the game). Check for a subject + verb.
Missing the comma before FANBOYS in long sentences.
Overloading. A compound-complex sentence is a tool, not a goal. Too many in a row makes writing hard to follow.