"Couldn´t" for expressing certainty

Status
Not open for further replies.

mafto

Junior Member
Joined
Mar 14, 2011
Member Type
Student or Learner
Native Language
Slovak
Home Country
Slovak Republic
Current Location
Slovak Republic
Hello,

would it be correct to say "He´s in Australia. The man waiting at the door couldn´t be him."?
If we´re not in Australia and therefore the man waiting at the door can´t be him. I know "can´t" is OK, but want to make sure what about "couldn´t".

Thank you.

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 couldn´t be him OR the man waiting at the door couldn´t 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 can´t find it.
Or should there be "couldn´t" only? It is normal in my language but I don´t know if you can jump in English from the past to the present like this :)

Thank you for all answers
 

billmcd

Key Member
Joined
Mar 27, 2009
Member Type
English Teacher
Native Language
English
Home Country
United States
Current Location
United States
Hello,

Would it be correct to say "He´s in Australia. The man waiting at the door couldn´t be him."?
If we´re not in Australia and therefore the man waiting at the door can´t be him. I know "can´t" is OK, but want to make sure what about "couldn´t". Either form is acceptable.

Thank you.

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 couldn´t be him OR the man waiting at the door couldn´t have been him.? "couldn't have been"

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 can´t find it.
Or should there be "couldn´t" only? It is normal in my language but I don´t know if you can jump in English from the past to the present like this :)
"Couldn't" suggests that the search has concluded. "Can't" indicates that the search has concluded, but suggests that possibility that the search may continue.
Thank you for all answers

b.
 
Status
Not open for further replies.
Top