Respuestas
Respuesta:
CAN
The three main uses of Can are: 1) ability 2) possibility and 3) permission. However there are some other used of Can as we will see below.
1. To express ability
Can means to be (physically) able to do something OR to know how to do something.
Birds can fly.
Elephants can't fly.
I can speak two languages.
2. To express a possibility (in general)
This refers to a theoretical possibility.
Note: we don't use can to talk about future possibilities. For this you would use may or might.
It can get cold there at night so take a jacket.
I know you can win the competition.
Well, I think your car can be repaired, but it's not going to be cheap.
3. To offer to do something for others
Can is used when you offer to help someone or to do something for them.
You don't need to walk home. I can take you there if you like.
Can I carry your bags for you?
COULD
Could is similar to Can and often replaces Can in the past tense (though not always)
1. To express ability in the past
I could ride a horse when I was younger but now I can't.
She could juggle eight balls when she was only 10 years old.
He could read when he was three years old.
2. Polite word used to ask for permission or to request something (in the present)
Could I please use your bathroom?
Could we move on to the next topic now please?
Could you pass me the salt please?
I'm busy right now. Could you call back later?
3. General permission in the past
In high school, we couldn't leave the classroom without a pass.
He couldn't go to the concert because his mother wouldn't let him.