Modal Verbs – Introduction

1. Common Modal Verbs

The most common modal verbs are:

can, could, may, might, must, shall, should, will, would

Sometimes we also include:

have to, need to, ought to

2. What Modal Verbs Express

Ability

We often use can and could for ability.

I can drive.
[Ich kann Auto fahren.]

She could read when she was four.
[Sie konnte lesen, als sie vier war.]

Permission

We often use can and may for permission.

Can I open the window?
[Kann ich das Fenster öffnen?]

You may leave now.
[Du darfst jetzt gehen.]

Obligation and Necessity

We often use must, have to, and need to for obligation or necessity.

You must wear a helmet.
[Du musst einen Helm tragen.]

I have to get up early.
[Ich muss früh aufstehen.]

We need to finish this today.
[Wir müssen das heute fertig machen.]

Prohibition

We use mustn't when something is not allowed.

You mustn't smoke here.
[Du darfst hier nicht rauchen.]

Advice

We often use should and ought to for advice.

You should drink more water.
[Du solltest mehr Wasser trinken.]

You ought to call your parents.
[Du solltest deine Eltern anrufen.]

Possibility

We often use may, might, and sometimes could for possibility.

He might be at home.
[Er könnte zu Hause sein.]

It may rain later.
[Es könnte später regnen.]

Probability or Expectation

We can use should to show probability or expectation.

The train should arrive soon.
[Der Zug sollte bald ankommen.]

3. Form of Modal Verbs

Modal verbs usually follow this pattern:

subject + modal verb + base form of the verb

Examples:

I can swim.
[Ich kann schwimmen.]

She must go.
[Sie muss gehen.]

They should wait.
[Sie sollten warten.]

After a modal verb, we use the base form of the verb.

Correct:
He can drive.

Not correct:
He can to drive.

4. No -s in the Third Person Singular

Modal verbs do not take -s with he, she, it.

Correct:
She can swim.

Not correct:
She cans swim.

5. Negative Forms

To make a negative, we add not.

• cannot / can’t
• must not / mustn’t
• should not / shouldn’t
• may not
• might not

He can’t drive.
[Er kann nicht fahren.]

You shouldn’t eat so fast.
[Du solltest nicht so schnell essen.]

We mustn’t be late.
[Wir dürfen nicht zu spät sein.]

6. Questions with Modal Verbs

To make a question, we put the modal verb before the subject.

Can you help me?
[Kannst du mir helfen?]

Should I call her?
[Sollte ich sie anrufen?]

May we come in?
[Dürfen wir hereinkommen?]

7. Important Difference: Mustn't vs. Don't Have To

This is a very important difference:

mustn't = it is prohibited
[es ist verboten / man darf nicht]

don't have to = it is not necessary
[es ist nicht notwendig / man muss nicht]

You mustn't park here.
[Du darfst hier nicht parken.]

You don't have to come early.
[Du musst nicht früh kommen.]

8. Quick Overview

can = ability / permission
must = strong obligation
mustn't = prohibition
should = advice
may / might = possibility
have to = necessity
don't have to = no necessity
ought to = advice
need to = necessity