Grammar · Modal Verbs

The verbs that show possibility and need

A modal verb is a special helper verb that changes how possible, likely, allowed or necessary something is. The modals are can, could, will, would, shall, should, may, might and must. Each is always followed by a plain verb (might rain, can swim). Learn what each one shows below.

1 What a modal verb is

A modal verb is a special helper verb that changes how possible, likely, allowed or necessary something is. The modals are: can, could, will, would, shall, should, may, might, must.

You must stop. · It might rain. · I can swim. ✓

2 A modal is followed by a plain verb

After a modal comes the plain (base) form of the next verb — no '-s', no 'to', no '-ing'.

✓ She can swim. · ✗ She can swims. · ✗ She can to swim.

3 What each modal shows

Abilitycan, could — I can ride a bike

Possibilitymay, might, could — it might snow

Permissioncan, may — you may leave

Obligationmust, should — you must wait

Adviceshould — you should rest

4 Strong or gentle?

Some modals are stronger than others. must is a strong obligation; should is advice; might is a small possibility; will is certain.

You must go (no choice) vs You should go (a good idea) vs You might go (maybe). ✓

Watch out could / should / would

These are modals too. could = ability/possibility in the past or a polite option; should = advice; would = a likely or imagined result.

I could help. · You should ask. · She would like that. ✓

The 30-second method

How to handle any modal question fast

Spotting one? Look for can/could/will/would/shall/should/may/might/must.
Check the next verb is plain (might rain, can swim).
What does it show? ability, possibility, permission, obligation or advice.
Strong (must) or gentle (might/should)?
Choosing one? Match the modal to the meaning the sentence needs.

10 worked examples

Read the question, then the answer with the rule that solves it.

1. Find the modal: You must listen.

must — shows obligation (Rule 1).

2. Find the modal: It might snow.

might — shows possibility (Rule 1).

3. Correct? — She can sings.

No — 'can sing' (plain verb) (Rule 2).

4. Which shows ability? — I ___ swim.

can — ability (Rule 3).

5. Which shows advice? — You ___ rest.

should — advice (Rule 3).

6. Which shows permission? — You ___ go now.

may — permission (Rule 3).

7. Stronger: must or might?

must — a strong obligation (Rule 4).

8. Polite request: ___ you help me?

Could (or Would) — polite (Watch out).

9. Which shows possibility? — It ___ be true.

may/might/could — possibility (Rule 3).

10. Plain verb after 'should'? — You should ___ .

go / wait / try — plain form (Rule 2).

Mock paper — 20 questions

Progress0 / 20

Pick one answer (A–E) for each question. The timer starts when you answer your first.