Circle the correct words in bold. Then write what the words in each sentence express (ability in the present/ past/future, opportunity to do something, ability in a specific situation in the past).
1 You can / could use the computer now if you like. (.............)
2 in 100 years, we can / will be able to go on holiday in space. (............)
3 The computer is working again. Nurislam was able to / could fix it in half an hour. (.........)
4 You can / are able to go out with your friends if you finish your homework now. (...........)

You can / could use the computer now if you like.
Correct answer: can
What it expresses: Ability in the present – The sentence talks about the possibility or permission to use the computer right now.

In 100 years, we can / will be able to go on holiday in space.
Correct answer: will be able to
What it expresses: Ability in the future – The sentence refers to a potential capability humans might have in the future (100 years from now).

The computer is working again. Nurislam was able to / could fix it in half an hour.
Correct answer: was able to
What it expresses: Ability in a specific situation in the past – This refers to a specific moment when Nurislam successfully fixed the computer.

You can / are able to go out with your friends if you finish your homework now.
Correct answer: can
What it expresses: Opportunity to do something – The sentence gives permission or opportunity contingent upon finishing homework.