Modal verbs of Prohibition Exercises, Examples, Rules

These exercises focus on Modal verbs of Prohibition

Modal Verb	Meaning	Example
must not	Strong rule or strict prohibition	You must not touch this button.
cannot	General restriction or impossibility	You cannot park your car here.
may not	Formal or polite prohibition	You may not enter the meeting room.

Basic Sentence Structure:

Subject + modal verb + base verb

Example: He must not run in the hallways.

Do not use “to” before the base verb.

Incorrect: You must not to eat here.
Correct: You must not eat here.

Illustration of Modal verbs of Prohibition

Differences Between Must Not, Cannot, and May Not

Modal Verb	Usage	Example
must not	Strong prohibition, usually for rules or warnings	You must not drive without a license.
cannot	Prohibition due to restriction or impossibility	You cannot enter this area.
may not	Formal or polite prohibition, often in official contexts	Students may not bring phones to class.

At school:

Students must not cheat during exams.
You cannot leave school before dismissal.
Visitors may not enter the library without permission.

At work:

Employees must not disclose confidential information.
You cannot access this file without a password.
Staff may not take personal calls during meetings.

In public places:

You must not smoke in the park.
You cannot park your car in a handicapped spot without a permit.
Passengers may not board the bus without a valid ticket.

Common Errors and How to Avoid Them

Mistake	Why It’s Wrong	Correct Version
He must not to speak loudly.	Adding “to” before the base verb.	He must not speak loudly.
They don’t must use phones.	Mixing modal verbs with “don’t.”	They must not use phones.
You mayn’t enter here.	Using the rare contraction "mayn’t."	You may not enter here.
We can’t to drive here.	Adding “to” before the base verb.	We can’t drive here.

Context	Modal Verb	Example
Strong, direct rule	must not	You must not bring food here.
General restriction	cannot	You cannot enter this area.
Formal or polite tone	may not	You may not use the staff entrance.

What is the difference between “must not” and “don’t have to”?

Must not means something is prohibited.

Example: You must not lie to your teacher.

Don’t have to means something is not necessary.

Example: You don’t have to wear a tie to the meeting.

Can I use “may not” instead of “must not”?

Yes, but may not is more formal and polite, while must not is stronger and stricter.

Example: Visitors may not take photographs in the gallery.

You must not touch the paintings.

What’s the difference between “cannot” and “may not”?

Cannot shows general restrictions or impossibilities.

Example: You cannot park here without a permit.

May not politely denies permission.

Example: You may not park here after 8 PM.

Can I use “should not” for prohibition?

No, should not gives advice, not prohibition.

Example: You should not eat too much junk food (advice).

You must not bring drinks into the lab (prohibition).

Is “mayn’t” ever used in modern English?

No, the contraction mayn’t is almost never used today. It’s better to say may not.

Modal verbs of Prohibition