Modal verbs: Can, Could, Be able to

..unfortunately this won't an example but, a dedication..

  

 

Motorcycles racers can fly high..

                                                     #58

Can and could are modal verbs. 

They are used with other verbs to transmit ideas such as possibility, permission, etc.


Can

We use can to say that something is possible or allowed, or somebody has the ability:

• talk about possibility and ability. example: - I can ride a motorbike.  - He can speak three languages.

• make requests or give orders. example: - Can you buy me a pencil?  - Can you complete your job before you leave the office.

• ask for or give permission. example: - Can I borrow your mobile for a second?

Could 
We use could:

• as the past tense of can. example:  - Guys, Tom is on his way and he said she could get the pizzas for us.

• to show what was possible in the past. example:  - He could ride the bike since he was nine years old.

• to ask someone to do something. example:  - Could you hold this bag for a second, please?

• to ask if someone is able or allowed to do something. example: - My grandmother could speak Spanish.  - Could I ask you an information?

 We could use could especially with verbs like: SEE, HEAR, SMELL, TASTE, FEEL, REMEMBER, UNDERSTAND
examples:- I could hear the sound of your voice from the upper floor.
- Yesterday afternoon was very hard to drive, I couldn't see anything.


Be able to
Be able to is used when we refer to somebody who has the ability to do something:
- Marta is able to drive, but she hasn't got a car.
- My grandfather was able to repair motorbikes.
- Applicants for the job, must be able to speak two foreign languages.


NOTE:
For general ability, the most common form is could.
But if we want to say that somebody did something in a specific situation, is possible to use was/were able to or managed to, rather than could.

examples: 
- I wanted to buy some bread, the first shop I went didn't have any, but I managed to go in another bakery.
- There was nobody to disturb me, so I was able to study the whole morning.


COMPARE:
- Marco was an excellent  motorcycle racer, he could drive really fast in races.
(Marco had the general ability to drive very well in competitions)

- Marco managed to win the Italian Minimoto Championship in 1999
(Marco won the title in that specific competition)