Choose the correct passive form of the given sentence:
Every visitor must sign the register at the main gate.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → The register must be signed by every visitor at the main gate.
Passive of “must” + verb:
| Change | Active | Passive | Why |
|---|---|---|---|
| Object becomes subject | the register | The register | The register receives the action, so it becomes the subject. |
| “Must” kept | must sign | must be signed | “Must sign” states a rule. In the passive, “must” stays and is followed by be + past participle (V3). |
| Agent (by ...) | Every visitor | by every visitor | The visitors are named as the doers, so they come after “by”. |
| Full sentence | Every visitor must sign the register at the main gate. | The register must be signed by every visitor at the main gate. |
“Can”, “may” and “should” work the same way: modal + verb → modal + be + V3. Example: Students may use calculators in this test. → Calculators may be used by students in this test.
Why the Other Options are Incorrect?
Option 1: The register must sign by every visitor at the main gate. — Incorrect. The word “be” is missing. Without it, the register becomes the one that signs.
Option 3: The register must have been signed by every visitor at the main gate. — Incorrect. “Must have been signed” guesses about something in the past. The active “must sign” is a rule for now.
Option 4: The register should be signed by every visitor at the main gate. — Incorrect. “Should” is not “must”. “Should” gives advice, but “must” states a rule.