The Core Difference

Passive Voice: Describes an ACTION being done to the subject.

Subject Complement: Describes a STATE or CONDITION of the subject.

Use these tests to determine which one you’re dealing with.

Test 1: The “By Whom?” Test (The Most Reliable Test)

Ask: “Can you add a by… phrase to indicate who performed the action?”

If YES → Passive Voice. You’re describing an action, and you can specify who did it.

If NO → Subject Complement. You’re describing a state, not an action performed by someone.

Examples:

“The window was broken.”

Can we say “The window was broken by the storm.”? Yes.

✅ This is Passive Voice.

“The woman is tired.”

Can we say “The woman is tired by her job.”? No, that sounds unnatural. We’d say “tired from her job,” but not “by.” The “by” test fails.

✅ This is a Subject Complement (describing her state).

Test 2: The “Very” Test

Ask: “Can you put the adverb very before the past participle?”

If YES → Subject Complement. “Very” modifies adjectives, not actions.

If NO → Passive Voice. You can’t modify an action with “very.”

Examples:

“The woman is tired.”

Can we say “The woman is very tired.”? Yes.

✅ This is a Subject Complement.

“The window was broken.”

Can we say “The window was very broken.”? No, that sounds wrong.

✅ This is Passive Voice.

Remember: Context is king! The same past participle can be one or the other depending on the sentence. For example, “The store is closed” could be a state (adjective) if it’s 3 AM, or a passive action if you say “The store is closed by the manager at 10 PM.”