Modal verbs with could, ability, request, suggestion, Conditional of Can, possibility, permission;
Ability
- I could play a guitar when I was a child
- I could smell something burning.
Request
- Could you hand me the pencil?
- Could I go to the park?
Suggestion
- I could help you with Spanish.
- They could go to the movies if you are interested.
Conditional of Can
- I could visit many places if I had more money.
Possibility
- A lof of crime could be prevented.
- You could have called first.
Permission
- Could I borrow your notebook?
- Could I speak to Mary?