would it be correct to say "Heīs in Australia. The man waiting at the door couldnīt be him."?
If weīre not in Australia and therefore the man waiting at the door canīt be him. I know "canīt" is OK, but want to make sure what about "couldnīt".
No. 2: If this happened in the past, what would the sentence look like? He was in Australia, so the man waiting at the door couldnīt be him OR the man waiting at the door couldnīt have been him.?
And No. 3 (unrelated to the title of this thread): Tell me, please, if it is OK to say: I wanted to bring you your book, I looked for it everywhere but I canīt find it.
Or should there be "couldnīt" only? It is normal in my language but I donīt know if you can jump in English from the past to the present like this :)
Thank you for all answers