Modal verbs (ability)

1. We use 'can/could' to express typical situations or behavior

• It can be difficult to find a summer job

2. We use 'can/be able to' for present and future ability

• Many children can type before they can write

3. We use 'can' for the future where there is a sense of opportunity

• They can visit the museum while they're here

4. We use 'could/couldn't' and 'was/were able to' to talk about general past ability

• I couldn't swim until I was 10 years old

5. We use 'could/couldn't' + perfect infinitive to talk about unfulfilled ability in the past

• I could have learnt to ski but I preferred skating