B1 · 20 Minutes

The Passive
with Modal Verbs

must should can may will
Context: California's State Parks & Campfire Rules
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Grammar Focus

4 min
modal verb  +  be  +  past participle
ModalMeaningExample
muststrong obligation / prohibitionCampfires must not be lit near dry grass.
shouldrecommendation / adviceGarbage should be put in bins.
canpermission / possibilityDogs can be taken into many parks.
mayweaker permissionCars may be parked in official lots only.
willfuture rule / certaintyNoisy dogs will not be allowed.
💡 Negative: modal + not + be + past participle  |  e.g. must not be lit   should not be built   will not be allowed
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Exercise 1 · Matching
Modal to Meaning
Match each modal verb to its correct meaning and example sentence.

Exercise 1 · Match the Modal to the Meaning

3 min

Match each modal (1–5) to its meaning (A–E) and example sentence (i–v).

Modals

1 must
2 should
3 can
4 may
5 will

Meanings

A Weaker permission — not certain
B Advice or recommendation
C Future rule — definitely will happen
D Strong obligation or prohibition
E General permission or possibility

Write your answers: 1–__   2–__   3–__   4–__   5–__

11 – Dmust = strong obligation / prohibition
22 – Bshould = advice or recommendation
33 – Ecan = general permission or possibility
44 – Amay = weaker permission — not certain
55 – Cwill = future rule — definitely will happen
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Exercise 2 · Gap-Fill
Campfire & Park Rules
Complete each rule using the correct modal passive form.
The modal and verb are given in brackets.

Exercise 2 · Gap-Fill

4 min

Complete each rule. Use: modal + be + past participle. The modal and verb are in brackets.

1Animal life at all times. (must / protect)
2Campfires near dry grass. (must not / light)
3Permits online. (can / order)
4Garbage in bins. (should / put)
5Cars in official lots only. (may / park)
6Dead wood from around the fire. (must / clear)
7Dogs on a short leash. (must / keep)
8Noisy dogs in the parks. (will not / allow)
9Picnic areas after use. (should / clean)
10Wildfires if rules are followed. (can / prevent)
1must be protected
2must not be lit
3can be ordered
4should be put
5may be parked
6must be cleared
7must be kept
8will not be allowed
9should be cleaned
10can be prevented
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Exercise 3 · Error Correction
Spot the Mistake
Each sentence has one mistake in the passive modal form.
Find it and write the correct version.

Exercise 3 · Error Correction

4 min

Each sentence contains one mistake. Find it, underline it, and write the correct sentence on the line below.

1Dogs should kept on a short leash at all times.
2Campfires must not lit near dry grass or in forest areas.
3Permits can ordering online or from your local fire department.
4Dead wood is must be cleared from around the campfire.
5Noisy dogs will not allowed in the parks.
6Picnic areas should be clean after use.
1should be keptmissing 'be'
2must not be litmissing 'be'
3can be ordered'ordering' → past participle 'ordered'
4must be clearedremove extra 'is'
5will not be allowedmissing 'be'
6should be cleaned'clean' → past participle 'cleaned'
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Exercise 4 · Transformation
Active → Passive
Rewrite each active sentence as a passive sentence.
Keep the same modal verb and meaning.

Exercise 4 · Sentence Transformation

5 min

Rewrite each sentence in the passive. You don't need to include the agent (by…) unless it's important.

Remember: Active: Rangers must clear dead wood.  →  Passive: Dead wood must be cleared.
1You should extinguish campfires completely before leaving.
Passive →
2Visitors must not feed the animals.
Passive →
3You can order permits from your local fire department.
Passive →
4Park rangers will not allow campfires during a fire ban.
Passive →
5You should leave picnic areas clean after use.
Passive →
6Everyone can prevent wildfires by following the rules.
Passive →
1Campfires should be extinguished completely before leaving.
2Animals must not be fed.
3Permits can be ordered from your local fire department.
4Campfires will not be allowed during a fire ban.
5Picnic areas should be left clean after use.
6Wildfires can be prevented by following the rules.

Wrap-Up · The Formula

modal verb  +  be  +  past participle
must
Strong obligation
Fires must not be lit.
should
Advice
Bins should be used.
can
Permission
Dogs can be taken in.
may
Weaker permission
Cars may be parked here.
will
Future rule
Dogs will not be allowed.
Common mistakes to avoid: ✗ Dogs should kept…  →  ✓ should be kept
✗ must be ordering  →  ✓ must be ordered
Negative form: modal + not + be + past participle
Fires must not be lit. Dogs will not be allowed.

🌲 Great work today!