Use of Can and Could with Examples, Modal Verbs Uses

Meaning and Uses of Can and Could

What are can and could where do we use them? Many people get confused when they come to use can and could in their writing because can and could are generally used interchangeably. In some cases, they don’t have any difference in their meanings, but in some cases, they completely change the meanings of sentences.
uses of can and could
Uses of can and could: The words can and could are called modal verbs. We use them in our speech and writing to express different meanings such as possibility, ability, suggestion, request, etc. They are always followed by the root form of a verb and aren’t followed by to. We do not change them, i.e., they are the same with all subjects.
The following are different ways to use can and could.
  • Ability
  • Possibility and Probability
  • Ask and Give Permission
  • Make Requests and Offers
  • Suggestions
We form affirmative sentences with them by putting them between the subject and verb. In questions sentences they go before the subject. To form negative sentences, put the word ‘not’ after can or could.  
Affirmative: Subject + Can/Could + Verb
Negative: Subject + Can/Could + Not + Verb
Interrogative: Can/Could + Subject + Verb

Different Uses of Can and Could

Asking or Giving Permission

Permission is needed when we want to be allowed to do something. We use can and could to ask for or give permission. Can is the least polite or formal than could. The negative form ‘can’t‘ is used for refusing permission.
  • Can I come to the party with dad? (asking for permission)
  • Can I borrow the bike? Yes, you can borrow it, but I need it early tomorrow.
  • They can stop work early today.
  • You can use my laptop today. (giving permission)
  • You can take some rice home with you.
  • Can you watch TV whenever you like?
  • He can’t enter the university without a student card. (refusing Permission)
We usually give permission with can. Could is used to ask general permission in the past or when asking for more important things. ‘Could’ is not used for refusing or giving permission.
  • Could I drink a little more? (Ask permission)
  • Could we stop work an hour early?
  • I am sorry, but you can’t. (Refusing permission using can’t not couldn’t)
  • One day a week, we could stay up late. (general permission)
  • Could I take your umbrella? (asking for Permission)
  • Could I say something?
  • Could you send this person a message from your phone, please?

Reporting Permission

We use Can and could for already been refused permission or permission that has already been given.
  • The engineer said I could visit the site as often as the manager liked.
Using could for past means somebody had permission to do something generally, but it does not use to talk about permission for one particular past action.
  • When we were at university, we could watch movies whenever we wanted.

Use of Can for Offers

We use Can I or Can we to offer to do something.
  • Can we help you with those dishes?
  • Can I carry your parcel?
  • Can I help you cross the road?
  • I’m afraid the manager has already left the office. Can I be of any help?

Uses of Can and Could (Ability and Lack of Ability)

We use both can and could for expressing someone’s ability. Can express ability in the present but could is used to express a person’s general ability that they possessed in the past. 
The negative of could is could not (contracted form couldn’t), which expresses a lack of general ability (not on one occasion) or lack of ability in a particular situation in the past.
  • Now: My son is 15 years old. He can read and write.
  • Then: When my son was six months old, he couldn’t read or write. (Could expresses ability in the past.)
  • My dog can run fast. (present ability)
  • Some animals can smell many things that humans can’t.
  • My son couldn’t use a computer when he was three. (general ability, not in a particular situation)
  • I tried hard but couldn’t lift the stone. (It means I have a lack of ability in that particular situation)
  • I tried but couldn’t operate the machine. (a particular situation)
  • I couldn’t speak English when I was at school. (generally)
  • Look! The baby can lift it.
  • Don’t push her into the water. She can’t swim.
  • She can come as early as we want her to.
  • I can draw outstanding scenery.
  • It’s hard to find someone who cannot have a master’s degree these days.
  • Can you ride? (Do you have the ability to ride)
  • Everyone can look at those animals at the zoo, but they can’t touch them. (it is allowed to look at them, but it is not allowed to touch them.)
  • Can you understand this language?
  • Can you read that board from here?
  • My dad can speak three languages.
  • I can see the whole village from my bedroom window.
  • You can’t lift that box.
  • I can’t see clearly in the dark. (I have a lack of ability)
  • I can climb trees, but I can’t fly.
  • Can’t you restore the phone?
  • I can’t play the guitar. (lack of ability in the present)
We also use can for future ability if we are talking about a possible plan.
  • I can’t phone him today, but I can meet him tomorrow.

Could for Past Ability

We use could for general ability, i.e., whenever someone wanted, they could do something at any time and for particular occasions in the past. The negative form is could not.
  • When my brother was young, he could play any musical instrument. (General ability)
  • I don’t know how fast she could type. (Past ability)
  • She could cook an enormous meal for us when we were at her home.
  • ‘Where is Ali?’ ‘He could be at the school.’
  • Could I ask you a question, sir?
  • My son couldn’t run until he was nearly three years old.
Can and could especially use with verbs of perception see, feel, hear, smell, remember, taste, and understand.
  • The hall was so noisy that I couldn’t understand his speech.
  • What can you see?
  • Can you remember where they live?

Use of Can and Could (Request Something)

We use can and could to ask someone politely for something or to ask to do things for us. Use Can you…? To make simple requests and express an informal relationship between the listener and the speaker. 
  • Can/Could I have your passport number and address, please?
  • Can you get those books down from the shelf for me?
  • If you see my dad, can you tell him I’m out of the house at night?
  • Can you write your name here, please?
  • Can I have those shoes in a smaller size?
  • You can stop that music right now! (Order)
We make requests with could, i.e., Could you..? that are more difficult for someone to fulfill.
  • Excuse me, could you tell me about the bus that goes to Oxford Street? (it is hard for the listener to fulfill this request)
  • Could you write your name here, please?
  • Could you put the book there, please? (request)
  • Could your brother phone me when he’s free?
  • Could you help me lift these chairs, please?
  • Could you lift the table a bit – I’ve got my pen caught under it?
  • Could you please be a little quiet?
We can also use can and could to ask to do something.
  • Could I use your glasses?
  • Can’t I leave before the end of the party?
  • Couldn’t students pay by credit card?
  • Can I speak to your dad, please?
  • Do you think I could borrow your laptop from you until tomorrow?

Express Possibility and Probability

We use can to talk about the general possibility (not for the possibility of something happening in a particular situation). We do not use can to say that something will actually happen or is actually true at this moment. We do not usually use can to talk about probability.
  • It can get very cold this month of the year.
  • Any student who wants to can learn this software. (can expresses whether the situation is possible in general)
  • Can gas freeze?
  • The temperature can reach 45°C in July. (The rising of temperature is generally possible)
  • Can you reach that lake in two hours? (Is it possible?)
  • Don’t go now. It could rain now.
  • Stone bridges can be pretty safe. (Here can express the occasional possibility. Sometimes it is possible to be pretty dangerous/Sometimes they are pretty dangerous.) 

Use Could for Past Possibility

We use could to say there is a possibility of something happening or to ask about the possibility of something happening. It can express present or future possibilities as well. Use negative of can and could to say that something is not the case.
  • Why Ahmad isn’t in class? He could be sick. (It expresses present time)
  • Dad could be home late today. (It expresses future time)
  • Several years ago, I could speak English fluently when I was in Edinburg. (It expresses a past time)
  • I could drive my car two years ago.
  • The window was open. Someone could get in.
  • Could it be that you don’t want to leave?
  • He was a person who could eat everything.
  • It could rain later tonight. (the possibility is less definite)
  • I couldn’t live in this house alone. (it wouldn’t possible for me)
  • There can’t/couldn’t be any students left in the classroom.
We also use ‘could’ to show our opinion about which we are unsure.
  • Why isn’t she present again?’ ‘It could be because her father is ill again.’
  • There could be some pizza left. I’ll go and check.
  • An accident could happen so quickly. (Probability)

Uses of Can and Could (Choices and Opportunities)

Can and could be used for present and future choices and opportunities or to suggest opportunities.
  • What shall I do? I can try asking someone for help.
  • What shall I do next Sunday? Well, you could watch a movie the whole day.

Some More Uses of Can and Could

We may use ‘can’ to describe a thing that frequently happens.
  • It can be very hot in Karachi in summer.
Use can and could to express willingness.
  • Yes, I can submit it again tomorrow if you want me to.
  • We could come back tomorrow if that is suited to your comfort.
We use ‘can’t’ to suggest that something should not happen.
  • You can’t leave the hall in the middle of his speech, can you? You’ll have to stay till the end.
Expressing certainty
  • The baby can’t be sleeping.
  • It can’t be 4. (I’m sure the answer is not 4)
Use can/could to talk about what is typical or talk about someone or something typical behavior.
  • A female crocodile can lay 20-30 eggs.
  • It could get very hot in July in our previous house.
Use could (often with strong stress) to criticize someone for not doing things.
  • You could smile sometimes!

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