B. Foundations of Language · Handwriting, Spelling and Sentences

Clauses, Phrases and Complete Sentences

B3.1 B3.3About 40 minutes

Learning goals

I can tell the difference between a phrase, an independent clause and a dependent clause.
I can use prepositional phrases to add detail to my sentences.
I can build simple, compound and complex sentences with clauses and phrases.
I can find and fix sentence fragments and run-on sentences.

Words to know

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

independent clause
A clause that makes sense on its own. It can be a sentence.

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

phrase
A group of words that work together but don't have a subject-and-verb pair, like under the bridge.

prepositional phrase
A phrase that starts with a preposition and ends with a noun or pronoun, like after school or with my aunt.

fragment
A piece of a sentence that is missing something, so it can't stand alone.

run-on sentence
Two sentences squished together without the right punctuation or joining word.

Remember from Grade 3

Every sentence has a subject (who or what) and a predicate (what the subject does or is). You built simple, compound and complex sentences, and you met prepositions like under, after and with.

In Grade 4 you'll learn the building blocks inside those sentences: clauses and phrases. Knowing them helps you write sentences that are complete, clear and interesting.

Clause or phrase?

A clause has a subject and a verb working together:

the wind howled (subject: wind, verb: howled)
because the bus was late (subject: bus, verb: was)

A phrase does not have a subject-and-verb pair:

under the snowy pine tree
after the hockey game
with my grandmother

All three of those are prepositional phrases. They start with a preposition and end with a noun. They tell where, when, how or with whom.

Two kinds of clauses

An independent clause makes sense by itself: We stayed inside.
A dependent clause starts with a word like because, when, if, although, after, before, since, while, until or unless. It depends on an independent clause: because it was snowing... (what happened?)

A complex sentence. The independent clause could be a sentence by itself. The dependent clause needs it.

Sentence form	Built from	Example
Simple	One independent clause (phrases can be added)	After school, my cousin and I skated on the pond behind the arena.
Compound	Two independent clauses + a comma + for, and, nor, but, or, yet or so	We wanted to skate, but the ice was too thin.
Complex	One independent clause + one dependent clause	Although it was raining, we played outside.

Sentence forms in Grade 4

Long doesn't mean compound

A simple sentence can be long! After school, my cousin and I skated on the pond behind the arena. has lots of words, but only one subject-and-verb team (my cousin and I / skated). The rest are prepositional phrases. One subject can even have two verbs: She smiled and waved. is still a simple sentence, and it needs no comma.

Commas with phrases and clauses

Compound: put a comma before the joining word: I like snow, but my dog doesn't.
Complex: if the dependent clause comes first, put a comma after it: When the bell rang, we lined up. If it comes last, you usually don't need one: We lined up when the bell rang.
Opening phrase: a comma after a long opening phrase helps the reader: In the middle of the night, the wolves howled. After a short one, the comma is up to you: At noon we ate.

Worked example

Let's take a sentence apart

Find the clauses and the prepositional phrase: When the bell rang, we lined up at the door.

Look for subject-and-verb teams. the bell rang (bell / rang) and we lined up (we / lined up). Two clauses!
When the bell rang starts with when, so it's a dependent clause.
we lined up at the door makes sense alone, so it's the independent clause.
at the door has no subject and verb. It starts with the preposition at: a prepositional phrase.
One independent + one dependent = a complex sentence. The dependent clause comes first, so there's a comma after rang.

Dependent clause: When the bell rang. Independent clause: we lined up at the door. Prepositional phrase: at the door. It's a complex sentence.

Fragments and run-ons

A fragment is only part of a sentence:

After the hockey game. (a phrase: no subject and verb)
Because it was snowing. (a dependent clause alone)
Ran to the bus stop. (no subject: who ran?)

A run-on squishes two sentences together: It was cold we wore our toques. Putting only a comma between them doesn't fix it: It was cold, we wore our toques. is still a run-on.

A fragment is missing a part. A run-on jams two sentences together. Joining the clauses correctly makes a complete sentence.

Worked example

Let's fix a run-on three ways

Fix: It was cold we wore our toques.

Find the two independent clauses: It was cold and we wore our toques.
Way 1: two sentences. It was cold. We wore our toques.
Way 2: compound. Add a comma and a joining word: It was cold, so we wore our toques.
Way 3: complex. Add a dependent word: Because it was cold, we wore our toques.

All three are correct. Choose the one that sounds best in your writing.

Worked example

Let's combine with prepositional phrases

Combine into one smooth sentence: The fox ran. It ran across the field. It ran at dawn.

The main idea is The fox ran.
across the field tells where. at dawn tells when. Both are prepositional phrases.
Put them together. A when phrase often sounds good at the start: At dawn, the fox ran across the field.

At dawn, the fox ran across the field. (still a simple sentence, but much richer!)

Just for fun

A dependent clause walked into the library. Because it wanted a book about...

Uh oh, that's a fragment! Somebody please finish this sentence.

Hands-on activity

Sentence strip builder

You need: paper strips (or sticky notes) in two or three colours if you have them, scissors (with a grown-up's help), and a pen.

On strips of one colour, write 4 independent clauses: the snow fell, my brother laughed, we built a fort, the dog barked.
On strips of another colour, write 4 dependent clauses: because the movie was funny, when the mail carrier came, after we ate lunch, while we slept.
On a third set, write 4 prepositional phrases: in the backyard, at the door, during the night, behind the shed.
Mix and match to build sentences. Try a simple sentence (clause + phrase), a complex one (clause + dependent clause), and a compound one (two clauses with and, but or so). Add capitals, commas and end marks.
Read each sentence aloud. Which ones are your favourites?
Try putting a dependent clause alone. Does it sound finished? That's a fragment!

Your turn

Phrase or clause? under the snowy pine tree

Independent or dependent clause? because the road was icy

Independent or dependent clause? the road was icy

Find the prepositional phrase: The cat slept on the warm blanket.

Simple, compound or complex? We wanted to skate, but the ice was too thin.

Simple, compound or complex? Although it was raining, we played outside.

Fix this fragment: After the hockey game.

More practice: warm-up

What two things does every clause have?

Name three words that can start a dependent clause.

Name the seven joining words for compound sentences.

Find the prepositional phrase: Meet me at the library.

Is Ran to the bus stop. a complete sentence?

More practice: on your own

Fix this run-on in two different ways: The wind howled the windows rattled.

Simple, compound or complex? In the morning, the geese flew south over the lake. Explain.

Add the missing comma: Because the bus was late we missed the assembly.

Does this need a comma? She smiled and waved. Explain.

Is It was late, we went home. correct? Fix it if not.

Challenge

Expand The bear slept. by adding two prepositional phrases. Then tell whether it's still simple.

Find every clause and phrase: My kokum smiled when we arrived at her house.

Write a complex sentence that starts with a dependent clause, and a compound sentence, both about spring. Check your commas.

Check your understanding

Quiz

Which is a phrase, not a clause?

Which is a dependent clause?

Which sentence is compound?

Which is a fragment?

Which is a run-on?

Where does the comma go? If you see a moose stay in the car.

For parents and teachers

Big idea: The Grade 4 Ontario Language curriculum (B3.1) asks children to identify and construct various sentence types and forms, including sentences built with prepositional phrases and with independent and dependent clauses. B3.3 covers the commas that go with them.

How to help at home:

When reading together, find a long sentence and ask: "How many subject-and-verb teams can we find?"
If your child writes fragments, read the fragment alone and ask, "Does that sound finished?"
Play "stretch a sentence": start with The dog ran. and take turns adding a prepositional phrase or clause.

Common difficulties:

Thinking long sentences are compound. Count the subject-verb teams, not the words.
Comma splices (two sentences joined with only a comma). Teach the three fixes.
Fragments that start with because. These are very common in Grade 4 writing.
Commas before every and, including in She smiled and waved.