In this lesson, we will learn how to express prohibition, rules, and restrictions in English using modal verbs. These expressions are essential for understanding what is not allowed or forbidden in various situations.
What are Modals for Prohibition?
Modal verbs for prohibition are used to express that something is not allowed, forbidden, or against the rules. The most common modals used for prohibition in English are:
| Modal | Usage | Formality Level |
|---|---|---|
| must not / mustn’t | Strong prohibition | Formal/Strong |
| cannot / can’t | General prohibition | Neutral |
| should not / shouldn’t | Advice against doing something | Mild suggestion |
| may not | Official prohibition | Very formal |
Must Not / Mustn’t
- You must not use your phone during the exam.
- Students mustn’t leave the campus without permission.
“Must not” (or its contracted form “mustn’t”) expresses a strong prohibition. It indicates that something is absolutely forbidden and there are serious consequences if the rule is broken.
Key points about “must not”:
- It’s used for strong prohibitions
- Often used in formal rules and regulations
- Implies serious consequences if violated
Cannot / Can’t
- You cannot park here.
- Visitors can’t enter this area without a pass.
“Cannot” (or its contracted form “can’t”) expresses a general prohibition. It indicates that something is not allowed or not possible according to rules or regulations.
Key points about “cannot”:
- Used for general prohibitions
- More common in everyday speech than “must not”
- Often used in public signs and notices
Should Not / Shouldn’t
- You shouldn’t eat too much sugar.
- Children shouldn’t watch too much television.
“Should not” (or its contracted form “shouldn’t”) is less strong than “must not” or “cannot.” It’s more like advice against doing something rather than a strict prohibition.
Key points about “should not”:
- Used for recommendations or advice
- Not as strong as “must not” or “cannot”
- Often used in giving health or social advice
May Not
- Students may not use calculators during the mathematics test.
- Visitors may not take photographs in this gallery.
“May not” is used for formal prohibitions, especially in written rules and regulations. It’s common in official documents, signs, and notices.
Key points about “may not”:
- Used in formal or official contexts
- Common in written rules and regulations
- Less common in everyday speech
Structure and Formation
The structure for using modals of prohibition is straightforward:
Subject + Modal + Not + Base Form of Verb + Rest of Sentence
Examples:
- You must not speak during the test.
- Children cannot play in this area.
- We shouldn’t waste water.
- Passengers may not smoke on the airplane.
Differences in Strength
The modals for prohibition can be arranged from strongest to mildest:
- Must not (strongest prohibition)
- Cannot/May not (strong prohibition)
- Should not (mild prohibition/advice)
Common Contexts for Prohibition Modals
Modal verbs for prohibition are commonly used in the following contexts:
| Context | Examples |
|---|---|
| Rules and regulations | Students must not cheat on exams. |
| Laws | You cannot drive without a license. |
| Health advice | You shouldn’t smoke if you want to stay healthy. |
| Safety instructions | Passengers must not stand up while the plane is taking off. |
| Public notices | Visitors may not feed the animals. |
Key Takeaways
- Modal verbs for prohibition help us express what is not allowed or forbidden
- The main modals used for prohibition are: must not, cannot, should not, and may not
- Different modals express different levels of prohibition, from strong (must not) to mild (should not)
- The structure is: Subject + Modal + Not + Base Form of Verb
- These modals are commonly used in rules, regulations, laws, and advice
Real-Life Examples
- You must not drive over the speed limit.
- Passengers cannot smoke on the plane.
- You shouldn’t leave your valuables unattended.
- Visitors may not take photographs inside the museum.
By mastering these modal verbs, you’ll be able to understand and express prohibitions clearly in English. Remember that the choice of modal depends on the strength of the prohibition and the formality of the situation.