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Modal verbs are an important grammar knowledge in English, helping you easily express many different meanings in sentences. So how to use modal verbs correctly? Join IDP to explore modal verbs in English and the diverse meanings that a verb can express. And don't forget to check your knowledge through the exercises below!

1. What Are Modal Verbs?

Modal Verbs, also known as auxiliary or helping verbs, are special verbs used to modify the meaning of the main verb in a sentence. They do not describe actions or states, but rather provide additional meaning such as ability, possibility, permission, obligation, or advice.

Examples of modal verbs: can, could, may, might, must, shall, should, will, would, ought to

Key Features of Modal Verbs:

  • Always followed by a bare infinitive (base form of a verb).

  • Do not take “s/es” in the third person singular.

  • Do not change for tense (e.g., no “-ed” or “-ing” endings).

  • Function only as helping verbs, never as main verbs.

2. Modal Verb Structure

Affirmative: Subject + Modal Verb + Verb (infinitive) + Object

Example: She can speak Spanish.

Negative:

Subject + Modal Verb + not + Verb (infinitive) + Object

Example: He should not be late.

Questions:

Modal Verb + Subject + Verb (infinitive) + Object?

Example: Can you help me?

Passive Voice with Modal Verbs:

Subject + Modal Verb + be + Past Participle

Example: The traffic rules must be obeyed.

3. Types of Modal Verbs by Function

3.1 Modal Verbs for Ability

Can / Could / Be able to

Use case

Example

Present or future ability

She can play the piano well.

Past ability

I could run faster when I was younger.

Permission or informal requests

Can I use your phone?

Polite requests

Could you help me with this?

Key difference:

  • Can = present or general ability

  • Could = past ability or polite permission

3.2 Modal Verbs for Advice

Should / Ought to

Use case

Example

Giving suggestions

You should study more for the IELTS test.

Expressing criticism or recommendations

You ought to stop smoking.

Advising someone not to do something

You shouldn’t stay up too late.

3.3 Modal Verbs for Obligation / Necessity

Must / Need (semi-modal)

Use case

Example

Expressing strong obligation or rules

You must wear a seatbelt.

Strong assumption

She worked all night, she must be exhausted.

Prohibition

You mustn’t use your phone in class.

3.4 Modal Verbs for Possibility / Certainty

May / Might / Could / Can

Use case

Example

Formal permission

May I speak to the manager?

Medium probability (≈50%)

Jack may arrive late.

Lower probability (≈30%)

It might rain tonight.

4. Modal Verb Practice Exercises with Answers

Exercise 1 – Fill in the blanks using correct modal verbs

  1. She told me that she was unwell, so she might not go to the office.

  2. The visitors must not carry food into the hotel.

  3. As he is in urgent need, we should help him immediately.

  4. Could you please lend me your book for a week?

  5. His son is not brilliant, but he might pass the exam.

  6. I shall be thankful if you help me.

  7. Drive fast or you may miss the flight.

  8. Would you like to come to the market with us?

  9. May I go out? I must meet my brother now.

  10. My parents might not allow me to travel alone as I am still sick.

Exercise 2 – Rewrite the following sentences

  1. Susan may know the address.

  2. Joanna might not have received my message.

  3. The report has to be on my desk tomorrow.

  4. I was able to finish all my work.

  5. Nancy didn’t need to clean the flat.

Use Modal Verbs Effectively with IDP IELTS Resources

Modal Verbs are a key grammar topic in English and frequently appear in both IELTS Academic and General Training. While not overly difficult, many learners confuse their meanings and usage if not practiced correctly.

With IDP, you can:

  • Access expert grammar guides and free learning materials.

  • Take a computer-based IELTS test at a time and place that suits you.

  • Try free mock tests at home or in test centers to evaluate your readiness.

When you're ready, register for your IELTS test with IDP and get expert guidance throughout your preparation journey.

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About this Article

Published on 26 December, 2023

About this Author

One Skill Retake - IELTS Australia
Quynh Khanh

Tôi là Quỳnh Khanh - Content Writer có hơn 5 năm kinh nghiệm về lĩnh vực giáo dục