Can, could, be able to

Here’s a refresher lesson on two modal verbs and ‘be able to’, which functions as one.
Lesson by Caroline Devane

Can

Is used to talk about possibility. e.g. ‘Can you meet me at 5?’
Is used to talk about ability. e.g. ‘I can ride a bike’.
Is used to make informal requests and orders. e.g. ‘Can you bring me my jumper?’
Has two negative forms,. can’t and cannot.

Could

Is used to talk about past abilities. e.g. ‘When I was a child I could do handstands’.
Is used to make formal requests. e.g. ‘Could you fax me that document by Tuesday?’
In the negative form, is couldn’t.

Be able to

Is sometimes used instead of can or could.
Can be used with all tenses. e.g. ‘I will be able to see you next week’.
Is used to talk about ability. e.g. ‘Are you able to write formal letters?’

Now that we’ve refreshed the basics, see if you can complete the following sentences correctly.

• 1. ___ you hear the fireworks from your house last night?
  
  Can't
  Could
  Can
  
  
• 2. Do you think you ___ write that report by Tuesday? I know you’re very busy.
  
  couldn't
  have been able to
  will be able to
  
  
• 3. I ___ touch my toes. See!
  
  could
  will be able to
  can
  
  
• 4. I ___ spend another moment in that restaurant. It was too noisy.
  
  couldn't
  can't
  have been able to
  
  
• 5. I ___ never seem to get the temperature right.
  
  can
  can't
  to be able to
  
  
• 6. ___ play professional tennis, you must be extremely fit.
  
  To be able to
  Couldn’t
  Will you be able to
  
  
• 7. ___ you play an instrument?
  
  Able to
  Can
  Couldn't
  
  
• 8. I'm afraid I ___ attend the meeting, I’m on business in Japan.
  
  will be able to
  can
  won’t be able to
  
  
• 9. ___ you have brought it to me at work?
  
  Will be able to
  Cannot
  Couldn't
  
  
• 10. They ___ save the men from the sinking ship.
  
  was able to
  could to
  were able to