Hi, To express the idea of "not beeing able to do something" can we say "couldn't do it"...I give you an example:
(situation: people are at a party) - Richard has to get up at 5am tomorrow! - After this party I wouldn't be able to get up so early!!
Can we replace the second sentence (without changing the meaning) by: -After this party I couldn't get up so early!! (I'd say that this sentence has not the same meaning, but Im not sure...)