"She could say yes, but she did not."
Translation:Вона могла сказати так, але не сказала.
Is there a way to express this sentence without using the verb a second time as in English?
No, you need to repeat the verb in such cases.
When English uses the verb ‘to do’ to avoid repeating the verb, Ukrainian usually repeat the verb. E.g. ‘I like it, I really do’ would be «Мені́ воно́ подо́бається, спра́вді подо́бається».
You could say "Вона могла сказати так, але не зробила цього" (She could have said yes but didn't do it/so). But it's not in any way shorter, if that's what you were shooting for :)
Isn't it wrong to use "could" in this sentence? Shouldn't it be "She could have said yes, but she did not"? If the information that "she did not" is already there, it's clear that it didn't happen so it should be "could have"... Or am I wrong?..
Oh man I just realized something.
"She could have said yes but she did not" = Вона могла би сказати так, але не сказала.
"She could say yes but she did not" = Вона могла сказати так, але не сказала.
The second one is in simple past. "She was able to say yes, but she did not".