( 14)  CAN and COULD

Can and could are modal verbs. They are used with other verbs to convey ideas such as possibility, permission, etc.

We use  can to:

• talk about possibility and ability;

Example: I can ride a horse. / He can speak three languages.

• make requests or give orders;

Example: Can you buy me a can of beer. / Can you complete now what you are doing.

• ask for or give permission.

Example: Can I come in now?

Note: we may also use could, may and might for permission.

Points to note:

• We use can for the present. We also use it for the future when           we decide we are able to do something.

Example: We can go swimming tomorrow.

• We do not use can with infinitive verb.

Example: We can play football today. NOT: We can to                     play football today.

• Sometimes it is necessary to use (be) able to in place of can.

Example: I can’t contact him. / I haven’t been able to contact him for two days. (It is not possible to use can with present perfect tense).

Could is one of the modal verbs. We use could:

• as the past tense of can.

Example: Jane said she could get the tickets for us .

• to show what was possible in the past.

Example: He could cycle when he was four years old.

• to ask someone to do something.

Example: Could you buy some cigarettes for me?

• to ask if someone is able or allowed to do something.

Example: My grandmother could speak Spanish. / Could I          ask you a question?

Points to note:

• Where the subject is singular, we do not add  –s to the verb

Example: He can swim. NOT: He can swims.

• We use could for actions now or in the future.

Example: It’s a nice day. We could go for a walk.

Example: When I go to London next week, I could stay                with my uncle.

• Could is less sure than can, so we use could when we do not           really mean what we say.

Example: I am so hungry. I could eat the whole chicken. (NOT: I can eat the whole chicken).

• We use could do for now and could have for the past.

Example: I am so tired. I could sleep the whole day.                    (now)

Example: I was so tired. I could have slept the whole                         day. (past)

• We use could with present perfect tense for things              which were possible to happen but didn’t or an event which we are not sure about.

Example: You could have taken a different route to                            avoid  the traffic jam.

Example: He could have broken the glass. She couldn’t                    have broken the glass.