Can't/couldn't for certainty

[Waawe]

Hello,

can we equally use can't/couldn't to say something is not possible?

Such as in:

It is too early, it can't/couldn't be the postman yet.

or

It was too early, it can't/couldn't have been the postman yet.

Thank you for diffusing my doubt about it and your time.

Waawe

[TheParser]

Hello,

can we equally use can't/couldn't to say something is not possible?

Such as in:

It is too early, it can't/couldn't be the postman yet.

or

It was too early, it can't/couldn't have been the postman yet.

Thank you for diffusing my doubt about it and your time.

Waawe

NOT A TEACHER


(1) It may/might not rain tomorrow. = Perhaps it will not rain.

(2) It can't/couldn't possibly rain tomorrow. = It certainly will

not rain.


Source: Mr. Michael Swan, Practical English Usage (1995 edition,

item #123.3 -- not page number).


Respectfully yours,


James