1. Lesson Overview
In this lesson, you will learn how modal verbs are used to form questions, negatives, and polite requests.
Modal verbs behave differently from ordinary verbs. They do not require auxiliary verbs such as do or does when forming questions or negatives.
Example:
She can analyse the data.
Question:
Can she analyse the data?
Negative:
She cannot analyse the data.
Modal verbs are also widely used to make polite requests, offers, and suggestions, especially in formal communication.
Example:
Could you review the report?
May I enter the laboratory?
By the end of this lesson, you will be able to:
-
form questions using modal verbs
-
form negative sentences with modal verbs
-
use modal verbs to make polite requests and offers
-
recognise differences between formal and informal requests
2. Concept Introduction
Consider the following statements:
She can operate the equipment.
To form a question, the modal verb moves before the subject.
Can she operate the equipment?
To form a negative sentence, the word not is added after the modal.
She cannot operate the equipment.
Modal verbs therefore follow simple structural patterns for questions and negatives.
3. Core Explanation
Modal verbs are auxiliary verbs that directly form questions and negatives without additional helping verbs.
Forming Questions
To create a question, place the modal verb before the subject.
Example:
Can the technician operate the machine?
This structure is called subject–auxiliary inversion.
Forming Negatives
To form a negative sentence, add not after the modal verb.
Example:
The technician cannot operate the machine.
Short forms are common in spoken English:
| Full Form | Contraction |
|---|---|
| cannot | can’t |
| could not | couldn’t |
| may not | — |
| might not | mightn’t |
| should not | shouldn’t |
Polite Requests
Modal verbs are often used to make requests politely.
Example:
Could you help me analyse the data?
The modal could makes the request more polite than can.
4. Rule Table
Modal Questions
| Structure | Example |
|---|---|
| modal + subject + base verb | Can she solve the problem? |
| modal + subject + be + complement | Could the results be inaccurate? |
Modal Negatives
| Structure | Example |
|---|---|
| subject + modal + not + base verb | She cannot solve the problem. |
| subject + modal + not + be | The results may not be correct. |
Polite Requests and Offers
| Modal | Example |
|---|---|
| can you | Can you help me with the report? |
| could you | Could you explain the results? |
| may I | May I enter the laboratory? |
| would you | Would you review the report? |
5. Usage
1. Asking questions
Example:
Can the technician repair the system?
2. Making polite requests
Example:
Could you review this report?
3. Asking permission
Example:
May I begin the experiment now?
4. Offering assistance
Example:
Would you like me to analyse the data?
5. Expressing inability
Example:
She cannot complete the experiment today.
6. Signal Words
Certain expressions commonly appear with modal verbs used for requests and offers.
| Expression | Example |
|---|---|
| please | Could you help me, please? |
| would you mind | Would you mind checking the results? |
| may I | May I ask a question? |
| could you please | Could you please review the report? |
| would you like | Would you like some assistance? |
These expressions make requests more polite and formal.
7. Special Cases
Can vs Could for Requests
| Modal | Level of Politeness | Example |
|---|---|---|
| can | informal request | Can you open the window? |
| could | more polite request | Could you open the window? |
May for Permission
May is traditionally used in formal permission requests.
Example:
May I enter the laboratory?
In informal contexts, can is often used.
Example:
Can I enter the laboratory?
8. Additional Notes
Modal verbs help express social politeness and formality.
In professional or academic contexts, speakers often prefer indirect requests.
Example:
Less polite:
Give me the report.
More polite:
Could you give me the report?
Using modal verbs helps maintain respectful communication.
9. Common Errors
⚠ Using “do” with modal verbs in questions
Incorrect:
Do you can analyse the data?
Correct:
Can you analyse the data?
Explanation:
Modal verbs do not require “do” support.
⚠ Incorrect negative structure
Incorrect:
She doesn’t can analyse the data.
Correct:
She cannot analyse the data.
Explanation:
Modal verbs form negatives without “do.”
⚠ Using “to” after modal verbs
Incorrect:
Could you to help me?
Correct:
Could you help me?
Explanation:
Modal verbs are followed by the base verb.
⚠ Incorrect word order in questions
Incorrect:
You can analyse the results?
Correct:
Can you analyse the results?
Explanation:
The modal verb must come before the subject.
⚠ Incorrect request structure
Incorrect:
May you help me with the report?
Correct:
Could you help me with the report?
Explanation:
May is normally used for permission, not requests.
10. Lesson Mastery
After completing this lesson, you should now be able to:
✅ form questions using modal verbs
✅ create negative sentences with modal verbs
✅ use modal verbs to make polite requests and offers
✅ distinguish between formal and informal modal requests