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Level: beginner

We use can and can't to talk about someone's skill or general abilities:

She can speak several languages.
He can swim like a fish.
They can't dance very well.

We use can and can't to talk about the ability to do something at a specific time in the present or future:

I can see you.
Help! I can't breathe.

We use could and couldn't to talk about the past:

She could speak several languages.
I couldn't see you.

Ability: can and could 1


Ability: can and could 2


Level: intermediate

We use could have to say that someone had the ability or opportunity to do something, but did not do it:

She could have learned Swahili, but she didn't want to.
I could have danced all night. [but I didn’t]

Ability: could have 1


Ability: could have 2



This was very helpful to improve my English knowledge

Thanks a lot. It was very helpful to impruve my English skills.

Thank you for such useful piece of grammar!
But.... i don't quite understand when we use "must" and when "have to" (in Present tenses)?

 Hi Olessya

I think (and not everyone agrees) that must expresses both obligation and authority.

Have to expresses obligation but the authority, or reason for the obligation comes from somewhere else.

When I was a child, the main authority figures in my life were my parents and they would say things like: "You must tidy your room!" Or: "You must work hard at school!" If I ever asked why, the answer was simply: "Because I said so!"

Must is for people in authority.

Teacher - student: You must do your homework.

Doctor - patient: You must eat more vegetables.

Expert - novice: You must listen very carefully.

I think you have to be careful when you use must because it can make people uncomfortable. If someone tells me to do something using must who is not an authority, a little voice in my head rebels and shouts "You're not my mum!"

Have to doesn't express authority. The authority comes from somewhere else.

In the UK, you have to wear a seatbelt in a car. Authority = it's the law.

When you are in the cinema, you have to turn off your mobile phone. Authority = cinema rules.

Sometimes, we use logic or reason as an authority. 

You have to put petrol in your car, not diesel. Authority = common sense (if you don't, it won't work)

Here's an example I use with my students:

I come from London so I know a lot about London. If one of my students is going to visit the UK, I might tell them: "Oh, you must visit the National Gallery."

I can say this because I've been there. I have never been to New York so if one of my friends is going to visit, I might say: "Oh, you have to visit Time Square!" This is not my authority, everyone knows about Time Square.  

One of my tutors when I was training described my interest in must / have to as an obsession and so I may be taking this too far but I hope it helps.


Jack Radford 

The LearnEnglish Team 


Hi Jack
my obsession with must and have to is as strong as yours (maybe even stronger). As far as school rules are concerned I wonder if it is better to use must or have to.
Students must wear uniforms comes from people in authority, but it is also a school rule (coming from somewhere else). Well, why can't I say Students have to wear uniforms then?
More examples: Students must do their homework / students have to do their homework.
Students must be punctual. / students have to be punctual.
Don't you agree?
Thanks for your most useful help (if any).
Ernesto from Italy

Hi Ernesto

This is an interesting example. Some of my teachers, the young friendly ones, would avoid using 'must' to deflect their students' negative reactions to being told what to do.

For example, if a young friendly teacher saw a student listening to an ipod (well, it would have been a walkman back then), they would tell the student to put the ipod away. However, they would appeal to the student saying:

"I understand you are upset. It's not my decision. It's a school rule, you have to put it away." 

Other teachers seemed to enjoy their roles as enforcers of the school's authority. They would be more likely to use must.

"You must listen to me!"



The LearnEnglish Team



Thank you so much for your priceless help!

thanks , from such helpful descriptions about "Must and Have to" so, I hope you be fine all times .

ohh this is something really helpful :)

its useful to learn something of this topics...