Building sentences that work
Sentences are the building blocks of writing. To build strong sentences you need two things: the right structure (how the parts fit together) and agreement (making sure the parts match). This tutorial explains both.
The two essential parts
Every complete sentence has:
- A subject: who or what the sentence is about.
- A predicate: what the subject does or is. It contains the verb.
| Subject | Predicate |
|---|---|
| The excited fans | cheered loudly. |
| My grandmother | grows tomatoes in her garden. |
| Sharks | have several rows of teeth. |
Simple and complete subjects
- The simple subject is the main noun or pronoun: fans.
- The complete subject includes all the words that describe it: The excited fans.
Compound subjects and predicates
- Compound subject: two subjects sharing a verb. Maya and Jordan played chess.
- Compound predicate: two verbs sharing a subject. The dog barked and wagged its tail.
Clauses
A clause is a group of words with a subject and a verb.
- An independent clause can stand alone as a sentence: I finished my homework.
- A dependent clause cannot stand alone; it begins with a word like because, when, if, although: because I had time.
Three sentence structures
Simple sentence
One independent clause. One complete thought.
The volcano erupted.
Lila and her sister built a sandcastle on the beach. (still simple: one subject group, one predicate)
Compound sentence
Two independent clauses joined by:
– a comma and a coordinating conjunction (for, and, nor, but, or, yet, so), or
– a semicolon.
The volcano erupted, and ash filled the sky.
I wanted to go; however, it was too late.
Complex sentence
One independent clause plus at least one dependent clause.
When the volcano erupted, the villagers fled.
The villagers fled because the volcano erupted.
Using all three types makes writing more interesting and lets you show how ideas connect.
Subject-verb agreement
The verb must agree with its subject in number. This rule is called subject-verb agreement.
- Singular subject → singular verb: The bird sings.
- Plural subject → plural verb: The birds sing.
Notice: in the present tense, singular verbs often end in -s, while plural subjects often end in -s. That is opposite of what many people expect!
Tricky situations
1. Words between the subject and the verb
The box of crayons is on the shelf. (The subject is box, not crayons.)
Tip: cross out prepositional phrases to find the real subject.
2. Compound subjects with and
Sam and Ali are friends. (Two subjects = plural.)
3. Compound subjects with or or nor
Match the verb to the subject closer to it.
Either the cats or the dog is making noise.
Either the dog or the cats are making noise.
4. Indefinite pronouns
Singular: everyone, everybody, someone, nobody, each, either, neither
Everyone is ready. Each of the students has a book.
Plural: both, few, many, several
Both are correct.
5. Collective nouns
Words like team, class, family, herd are usually singular when the group acts together.
The team is practising.
6. Sentences beginning with there or here
The subject comes after the verb. There are three apples. There is one apple.
Pronoun-antecedent agreement
A pronoun must match the noun it replaces (its antecedent) in number. This is pronoun-antecedent agreement.
- The students finished their projects.
- The dog wagged its tail.
- Each girl brought her lunch.
When the antecedent is a singular indefinite pronoun like everyone, many writers now use their: Everyone brought their lunch. This is widely accepted, but in formal writing you may also rephrase: All the students brought their lunches.
Worked examples
Example 1: The list of supplies (is / are) long.
Subject: list. Answer: is.
Example 2: Neither my brothers nor my sister (likes / like) broccoli.
Closest subject: sister (singular). Answer: likes.
Example 3: Identify the structure. After the storm passed, we went outside.
Dependent clause + independent clause = complex.
Example 4: Fix the agreement. Every student must bring their own pencil.
Acceptable in everyday writing; formal option: All students must bring their own pencils.
Common mistakes
- Matching the verb to a nearby noun instead of the true subject.
- Treating everyone as plural. Everyone are here → Everyone is here.
- Using only simple sentences, which makes writing choppy.
- Joining two sentences with only a comma (a comma splice). Add a conjunction.
- Pronoun mismatch. The team lost their game is fine in Canadian everyday speech, but The team lost its game is the formal choice.
Try it yourself
- Underline the subject and circle the verb: The tall trees in the park sway in the wind.
- Choose: Each of the puppies (has / have) a collar.
- Choose: There (is / are) many reasons to recycle.
- Label as simple, compound or complex: I like pizza, but my brother prefers tacos.
- Combine into a complex sentence: We went inside. It started to rain.
Answers: 1. Subject: trees; verb: sway. 2. has. 3. are. 4. compound. 5. We went inside because it started to rain.
Study tip
When editing, read each sentence and find its subject first, then check the verb. For long sentences, lightly cross out prepositional phrases in pencil so the true subject stands out.
Quick recap
- Every sentence needs a subject and a predicate.
- Simple sentences have one independent clause; compound sentences have two; complex sentences add a dependent clause.
- Subjects and verbs must agree in number.
- Watch for words between the subject and verb, indefinite pronouns and compound subjects.
- Pronouns must agree with their antecedents.