Ability


Modals for Ability
When describing ability there are two main criteria to consider:
  • Referring to a Single Specific Occasion or General Ability.
  • Referring to the PAST, PRESENT, FUTURE or HYPOTHETICAL time.
Can & Could

Can / Can't
Use Can / Can't for General Ability in the Present.
  • I can swim.
  • She can't drive a bus.
Use Can / Can't for Specific Ability in the Future.
  • I can come on Friday, if you want.
  • Can they come to my party?
Note: CAN is used without TO.
  • I can fix your bike.
    • NOT I can to fix your bike.
Could / Couldn't
Use Could / Couldn't for General Ability in the Past.
  • I couldn't write when I was 4.
  • She could speak three languages 10 years ago.
Use Could / Couldn't for Hyothetical Ability in the Future.
  • We could come later if it isn't raining.
  • Couldn't they fix it next week?
Use Could / Couldn't for Specific Ability in the Past, especially with state verbs.
  • We could smell the dinner from the other room.
  • Couldn't you hear the dog barking?
Could Have / Couldn't Have
Use for Hyothetical Ability in the Past.
  • We could have gone to America, but we chose not to.
  • They couldn't have helped us anyway, they were away that weekend.

Managed to & Be Able to

Managed to & Was/Were Able to
Used for Specific Ability in the Past, especially when it was difficult.
  • She managed to finish that report on time.
  • I didn't manage to do the shopping today, sorry.
  • He wasn't able to study because he was ill.
  • I was able to read it in Dutch.
Will Be Able / Won't Be Able
Use for Specific Ability in the Future, similar to use of Can.
  • I will be able to come if you want.
  • Will they be able to deliver it tomorrow?
Would Be Able / Wouldn't Be Able
Use for Hyothetical Ability in the Future, similar to this use of Could.
  • I would be able to come if I finish work.
  • She wouldn't be able to help because she doesn't speak Danish.
Be Able To
In general the same as CAN, but note the following:
Has the negative form UNABLE, as well as a negative auxiliary.
  • They were unable to help. / They weren't able to help.
  • She will be unable to come. / She won't be able to come.
Unlike Can, BE ABLE TO can follow another modal.
  • She could have been able to do it.
  • I must be able to drive my car.