giovedì 20 novembre 2014

Past ability and possibility


Past ability & possibility

 
In the present tense we use ‘can’ to talk about a general ability – e.g. I can swim – and also for ability at a particular moment – e.g. I can see you! The rules for talking about past abilities are different.

General ability

We use could to talk about general abilities in the past.
  • He could speak fluent French when he was 5.
  • I could read before I started school.
Ability on one occasion

However, when we talk about ability on one particular occasion, we can’t use could
  • The burglar was able to get in through the bathroom window.
  • The burglar managed to get in through the bathroom window.
We have to use was able to or managed to. We can’t use could.
  • The burglar could get in through the bathroom window.
Ability on one occasion - negative

When we talk about a particular occasion when something wasn’t possible, we can use wasn’t/weren’t able todidn’t manage to, or couldn’t
  • The burglar wasn’t able to get in through the window.
  • The burglar didn’t manage to get in through the window.
  • The burglar couldn’t get in through the window.
Hypothetical past ability

Sometimes things were possible in the past but didn’t happen.
  • I could have gone to university but I decided to get a job.
  • I would have been able to win the race but I fell over.
We use could have (+ past participle) or would have been able to to talk about these hypothetical events. They can be used in the positive and the negative.
  • I couldn’t have done it without your help.
  • I wouldn’t have been able to afford it even if it had been for sale.
- See more at: http://learnenglish.britishcouncil.org/en/grammar-reference/past-ability-possibility#sthash.JddrcE1x.dpuf

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