Can: forms
Affirmative (+) form
Cancomes firstin the verb phrase (after the subject and before another verb):
We[verb phrase]cantakethe train to Birmingham.
Canis never used with another modal verb:
Hecanhear the music from his room sometimes.
Not:He can might hear the music… orHe might can might hear the music…
Negative (−) form
The negative form ofcaniscan’t. We don’t usedon’t/doesn’t/didn’twithcan:
Ican’tbelieve you said that!
Not:I don’t can believe you said that!
We can use the full formcannot(one word) in formal contexts or when we want to emphasise something:
Icannotunderstand why she behaves like that.
See also:
Modality: forms
Question (?) form
The subject andcanchange position to form questions. We don’t usedo/does/did:
Can thisreally be true?
Not:Does this can really be true?
Can’t youask for another day off work?
We usecanandcan’tin question tags:
You can’t take photos inside the museum,can you?
Abby can speak Japanese,can’t she?
Can: uses
Permission
We often usecanto ask for or give permission:
CanI take Daisy for a walk?
Studentscanuse calculators during the exam.
We usecan’tto forbid (say what you must not do):
Youcan’tpark there.
Youcan’tjust take the day off work. You have to have permission in advance.
See also:
May
Ability
We often usecanto talk about ability to do something in the present or future:
Icansing one song in Polish.
Canyou sleep on your back?
Wecango swimming after school tomorrow, if you like.
We often usecanwith verbs of perception such ashear, see, smell, taste, and mental process verbs such asguess, imagine, picture, understandandfollow(in the sense of ‘understand’):
Icanhear you.
Icansee her coming down the road now.
Canyou smell something burning?
Icanguess why you’re angry.
Wecan’tfollow these instructions for installing this new DVD player.(We can’t understand these instructions.)
General truths
We usecanto talk about things which we think are usually, but not always, true:
Reducing cholesterol through dietcanbe difficult.(It’s not always difficult for everyone, but in general it is difficult.)
Fireworkscanfrighten pets.
Swanscanbe very vicious.
We don’t normally usecouldto talk about what we believe to be true in the present.
| I believe this is a general truth or fact. |
| I see this only as a possibility. |
| I believe this is a general truth orfact based on my experience or knowledge. |
| I see this only as a possibility. |
See also:
Could
Possibility
We usecanto express possibility or to question possibilities:
Wecango to Rome in June because both of us have a week off work.(It is possible for us to go to Rome because we don’t have to work in June.)
Well, howcanyou be on a diet if you buy so much chocolate?(I don’t think it’s possible that you are on a diet because you still buy lots of chocolate.)
Guessing and predicting:can’tas the negative ofmust
When we want to guess or predict something, we use can’tas the negative form ofmust. We usecan’t have +-edform as the negative form ofmust have +-ed. Can’tandcan’t have +-edform express strong possibility:
A:Who owns this blue coat? Itmustbe yours.
B:Itcan’tbe mine. It’s too big. (A usesmustto guess that the coat belongs to B. He sees this as a strong possibility. B usescan’tto express strong negative possibility. The coat is too big, so it isn’t his.)
A:Roymusthave made a lot of money.
B:Hecan’thave done. He doesn’t even own a house. (A makes a deduction that Roy has made a lot of money. B sees this as very unlikely and so expresses it as a negative possibility.)
See also:
Must
Could
Requests
We usecanas a question form to make requests:
Those cakes look so good.CanI try one?
CanI have your surname?
Canyou help me with this form?
See also:
Could
Requests
Reproaches
We usecan’tas a question form to ask people to stop doing something we don’t want them to do, or to do something they are not doing which we want them to do:
Can’tyou stop making that awful noise?
Whycan’tyou just be nice to her instead of upsetting her?
Offers
We usecanas a question form to make offers:
CanI help you lift that?
Canwe do anything for you?
See also:
Offers
Can: past
The past ofcaniscould:
In those days, youcouldbuy everything in the local shop. Now we have to go to the big supermarket for everything.
We asked the security guards if wecouldgo backstage to meet the band.
When we question the possibility of something in the past, we usecan’t have+-edform:
Youcan’t have arrivedhere earlier than me.
Can: typical errors
We writecannotas one word:
The childrencannotbe left unsupervised at any time.
Not:The children can not be left unsupervised…
We usecould, notcan, to talk about ability in the past.
Theycouldsee a light on in the house as they drove past at 10 pm.
Not:They can see a light on in the house…