Ответ:
Is this really true?
Is / Is it too late?
Is it so cold?
Was it so cold?
Do you believe him?
Is he a doctor?
Is she really telling the truth?
Has he seen us?
Did they lose?
It cannot be that she did not find this book, it can be found in any library.
He cannot be warned.
He couldn't recognize you.
It can't be that he sings in the next room.
He couldn't tell you this. = It can't be that he said it.
They couldn't lose. = It can't be that they lost.
You couldn't see him there: he's sick now. = It can't be that….
Could you give me your pencil for a minute?
Could you wait a bit?
Could you come in a little later?
Can I see you there tonight?