If you put some ingredients in the refrigerator overnight, ...

[MichaelLu2000]

You're still missing the fact that "can" is the present simple and "will be able to" is the future voice. Of course they're not interchangeable!

I know they are of different tenses. But can and will be able to ARE interchangeable, while “can’t” and “won’t be able to” ARE NOT interchangeable.

If it stops raining tonight, we can play basketball in the park=If it stops raining tonight, we will be able to play basketball in the park.

If it rains tonight, we won’t be able to play basketball in the park (you can’t use “can’t”)

See the obvious difference?

In the first example, both can and will be able to are fine even though they are different tenses, and a future time point (tonight) is mentioned.

In the second, only “won’t be able to” can be used.

Also, you miss the point that in my original sentence of this post: If you put some ingredients in the refrigerator tonight, I **can**cook tomorrow night.

I obviously use the present tense “can” even though the cooking is going to happen tomorrow night, and another native speaker just says this sentence is fine.

It’s the perfect example of the interchangeability of “can” and “won’t be able to” when the time point is obviously future, so I really don’t understand why you don’t think that can and will be able to are interchangeable.

 

[Red5]

Please delete "Chien Te Lu" I am the owner of the these two accounts.

Hi there. I have merged your old account into your current account for you now.

 

[5jj]

If it stops raining tonight, we can play basketball in the park=If it stops raining tonight, we will be able to play basketball in the park.

If it rains tonight, we won’t be able to play basketball in the park (you can’t use “can’t”)

We can.

 

[MichaelLu2000]

We can.

Then I don’t know now. emsr2d2 says that they are not interchangeable so I am not sure now.

 

[jutfrank]

In the second, only “won’t be able to” can be used.

That's not true.

 

[dunchee]

Then I don’t know now. ...

Easy. Just stop thinking about "interchangeable."

From Practical English Usage 3rd edition, by Michael Swan
{quote}
123 can and could (3) ability (...)
1 future: can or will be able
We use can to talk about future actions which we will be able to do because of present ability, present circumstances, present decisions etc.
...
- Can you come to a party on Sunday?

In other cases we prefer other structures, for example will be able to.
- I'll be able to speak French at the end of this course.
(NOT I can speak French ... )
...
{end quote}