Modal verbs: Can you feel the love tonight?

By Phil Stoneman March 3, 2020

Could’ve, would’ve, should’ve, didn’t. Can you use modal verbs correctly, or might you make a mistake? Follow our guide and you should be perfect.

You mustn’t steal signs telling people what they can’t do! Credit: Pixabay

It’s difficult to know how you should study English nowadays. There are so many options! You could use apps, but perhaps you ought to enrol in a language school to get some extra support. Whatever you choose, you have to study every day: that’s really important.

It’s difficult to know how you should study English nowadays. There are so many options! You could use apps, but perhaps you ought to enrol in a language school to get some extra support. Whatever you choose, you have to study every day: that’s really important.

In our daily lives, we do a lot of different things. We talk about the things we’ve learnt to do, and we ask for permission to do those things. We check what we need to remember when we’re doing them, we make suggestions to others about the best ways to do them, and even try to predict what will happen as a consequence.

Fortunately, there’s an easy solution for all these situations: Modal verbs are your flexible friends in the world of English, and essential for many situations. Read on as we talk about some of the different types of modal verbs.


Are you a great guitarist? Or do you enjoy riding a bike? We all enjoy talking about our abilities. When talking about the present, we use can and can’t to talk about the things that we are and aren’t able to do, and could and couldn’t to talk about similar ideas from the past:

  • I will have to take a taxi to get there, because I can’t drive.
  • She could speak French when she was just ten years old.

Although not a modal verb, it’s important to also understand and use the phrase be able to. This has a similar meaning to can and could, but is much more flexible. You just need to know how to conjugate the verb to be:

  • I’ve been able to swim since I was a child.
  • My friend has lots of money. He might be able to lend us some.

Requesting and giving permission:

Do you need a favour? Or do you need someone to let you do something? Then can and could are also very useful:

  • Could I leave a little earlier today?
  • You can use your phone after you finish your work.

This is one area of language where some people say that can is not a good option, as a phrase like “Can I use your toilet?” might be talking more about your physical ability to use a toilet, and not the required permission. These people will say that “May I use your toilet?” is a much better option, but in practice, can is frequently used in this way.

Advising and suggesting:

We all have problems in life, but fortunately we also have friends who will suggest possible solutions. To give advice, we can use should or could:

  • You should take a painkiller if you have a headache.
  • You could take a taxi to get there faster.

Another option is to use the semi-modal verb, ought to. This has a similar meaning to should and could, but is a semi-modal as it uses to. Notice that this to is an important part of the verb, so you need to include it, even when ought to is at the end of a sentence:

  • You ought to visit your friend if he’s sick.
  • I know you don’t want to eat vegetables, but you ought to.

To give a lot of emphasis to a suggestion or advice, we use must.

  • You must visit Longstanton Spice Museum!
  • If you have a cold, you must stay in bed.


An unfortunate part of life is that there are a lot of rules. Some of these are very important, but we can safely ignore others.

When something is very important and it’s a necessity to follow the rule, we can use must or have to. Some grammar guides say that must is used when a particular obligation is something I’ve decided is important, and have to is for a rule which someone else has decided, but in practice these two forms are very similar:

  • You must wear a seatbelt when you drive.
  • She has to take her dog for a walk every evening.

When something is a possibility but not essential, we can use don’t have to to explain that this is optional:

  • He doesn’t have to wear a tie if he drives a taxi.

Finally, when something is definitely against the rules, we can use mustn’t:

  • You mustn’t drink and drive. You will lose your driving license.


Some things in life are easy to understand. Sometimes though, we have to guess. To make these deductions about something that is happening now, we can use must when we’re sure that something is true, might, may or could when we’re not sure, and can’t when we’re sure that something is not true:

  • He’s just finished running a marathon; he must be exhausted!
  • I’ve seen her around the hospital many times. She might / may / could be a doctor.
  • They’re only twelve years old! They can’t be university students!

We can also use the same modal verbs to make deductions about the past. To do this, we just put the verb after the modal verb into present perfect:

  • They went straight to bed when they arrived. They must have been very tired.
  • She has spent a lot of time in Europe. She might / may / could have visited Spain.
  • The food can’t have been cooked properly, because we all felt bad afterwards.

Seeing double

Be careful: One tricky thing about modal verbs is that the same modal verbs can be used in different situations, with different meanings. For example, the phrase she should be sleeping now could mean a) I’m a critical parent who wants a friend’s daughter to be in bed, or b) I’m a teenager who predicts that my mum is now in bed, so it’s time to sneak out for a party. Everything depends on context, so think about it carefully!


Modal verbs work a little differently from normal verbs. They are not conjugated, so there’s no need to use the “s” for third person. In addition, the verb that comes after the modal verb is used in its base infinitive form, without to. Check the following examples to see some common conjugation mistakes with modal verbs and how to correct them:


He cans work every day.

She must to wear a uniform.

They could saw the film.


He can work every day.

She must wear a uniform.

They could see the film.

Originally from Sheffield, England, Phil Stoneman has been living in Bogotá and teaching English since 2004. He teaches at Externado University, where he might have a great semester if his students realise they ought to arrive on time.