This time in our structure help we talk about using ‘can’, ‘could’ and ‘be able to. These words are sometimes used in the same situations, but there are some situations where that isn’t possible. Today we’ll look at some of those differences.
We use ‘can’, ‘could’ and ’be able to’ to talk about ability. We generally don’t use ‘be able to’ when the idea is ‘know how to’.
I can fly a plane (instead of ‘I’m able to fly a plane’).
We also don’t use ‘be able to’ to talk about something which is in progress. Consider the following example;
Look at that! He can perform a crab landing
(instead of ‘he is able to perform a crab landing’).
To talk about a specific example of ability in the past, we usually use ‘be able to’ instead of ‘could’.
Even though the weather was bad yesterday, we were able to land (not we could land).
They were able to resolve the problem before the flight last week and depart on time.
But ‘could’ is more natural in negative sentences related to a specific example of ability.
The weather was terrible and we couldn’t land.
The passengers couldn’t board due to a problem with the landing gear.
Try to think of some more examples to show these differences.
Have a great day!