Active vs Passive Voice

In the active voice, the subject performs the action. In the passive voice, the subject receives the action. Understanding both helps you vary your writing style.

Active Voice

The subject does the action. Clearer and more direct.

The cat chased the mouse.

Shakespeare wrote the play.

The chef prepared the meal.

Subject (doer) Verb Object

Passive Voice

The subject receives the action. Uses "was/were" + past participle.

The mouse was chased by the cat.

The play was written by Shakespeare.

The meal was prepared by the chef.

Subject (receiver) was/were + verb by + doer

When to Use Each

Active is usually better — it is clearer and more direct. Use passive when you want to emphasise the action or the receiver, or when the doer is unknown: "The window was broken" (we don't know who did it).

Subject-Verb Agreement

The verb must agree with its subject in number. A singular subject takes a singular verb; a plural subject takes a plural verb.

✓

"The dog runs in the park." (singular subject, singular verb)

✓

"The dogs run in the park." (plural subject, plural verb)

✗

"The dogs runs in the park." (plural subject with singular verb — incorrect!)

Tricky Cases

• Each and every are always singular: "Every student has a book."
• Neither...nor — the verb matches the nearest subject: "Neither the teacher nor the students were late."
• Collective nouns (team, class, family) are usually singular: "The team is winning."

Relative Clauses

A relative clause gives extra information about a noun. It starts with a relative pronoun: who (people), which (things), or that (people or things).

Using "who" (for people)

The girl who won the race was very happy.

Using "which" (for things)

The book, which was very old, fell apart.

Using "that" (for people or things)

The cake that she baked was delicious.

Main clause Relative clause

Commas with Relative Clauses

If the relative clause adds extra information that could be removed, use commas: "My sister, who lives in Perth, is visiting." If the information is essential to identify the noun, do not use commas: "The student who studied hardest got the best mark."

Modality: Modal Verbs

Modal verbs show how certain or necessary something is. They indicate possibility, ability, permission, or obligation.

Certainty Level	Modal Verb	Example
Strongest (obligation)	must, shall	You must wear a seatbelt.
Strong (expectation)	should, ought to	You should finish your homework.
Medium (possibility)	could, may	It could rain later.
Weakest (slight possibility)	might	She might come to the party.

Remember: Choosing the right modal verb changes the strength of your sentence. In persuasive writing, use must and should for strong arguments. In balanced writing, use could and might to show uncertainty.

Key Vocabulary

Active Voice

A sentence where the subject performs the action (e.g., "The dog bit the man").

Passive Voice

A sentence where the subject receives the action (e.g., "The man was bitten by the dog").

Relative Clause

A clause that gives more information about a noun, introduced by who, which, or that.

Modal Verb

A verb that shows possibility, ability, permission, or obligation (must, should, could, might).

Subject-Verb Agreement

The rule that singular subjects take singular verbs and plural subjects take plural verbs.

Relative Pronoun

A word that introduces a relative clause: who, which, that, whose, whom.

Worked Examples

See how to transform sentences and identify grammar features.

Example 1: Active to Passive

Active: The gardener planted the roses.

Passive: The roses were planted by the gardener.

The object (roses) becomes the subject. The verb changes to "were planted". The original subject moves after "by".

Example 2: Adding a Relative Clause

Simple: The teacher gave out the prizes.

With relative clause: The teacher, who was smiling broadly, gave out the prizes.

The relative clause adds extra information about the teacher.

Example 3: Choosing Modal Verbs

Certain: You must arrive by 9am. (obligation — no choice)

Advisory: You should arrive by 9am. (recommendation)

Possible: You could arrive by 9am. (one option)

Uncertain: You might arrive by 9am. (slight possibility)

Knowledge Check

Test your understanding of advanced grammar. Select the correct answer and click "Check Answer".

Question 1

Which sentence is in the passive voice?

The dog chased the ball. The ball was chased by the dog. The dog is very fast. The dog ran quickly.

Question 2

Which sentence has correct subject-verb agreement?

The children was playing outside. Every student have a pencil. The team is ready for the match. She run every morning.

Question 3

Which relative pronoun should complete this sentence? "The scientist ___ discovered the cure was awarded a medal."

which when where who

Question 4

Rewrite this active sentence in the passive voice: "The storm destroyed the bridge."

The bridge was destroyed by the storm. The storm was destroyed by the bridge. The bridge destroyed the storm. Destroyed was the bridge by the storm.

Question 5

Which modal verb shows the strongest level of obligation?

might must should could

Advanced Grammar

Active vs Passive Voice

Active Voice

Passive Voice

When to Use Each

Subject-Verb Agreement

Tricky Cases

Relative Clauses

Commas with Relative Clauses

Modality: Modal Verbs

Key Vocabulary

Worked Examples

Knowledge Check

Key Concepts Summary