CitySpeak said:jiang said:Is the sentence 'You can't have seen him last week. He was in New York' correct? Shouldn't it be 'couldn't' instead of 'can't' since it is 'last month'?
I think the "can't have + past participle" form is used mostly in British English. I would wait for a BE speaker to comment on that.
It exists in American English, but as I can recall, it's not something I've heard or read often at all.
Here is a link to that form on a grammar site.
It also has a relatively small amount of hits on Google. The form exists, but it's simply not something one often encounters in Amercan English. I think your best bet is to stick with "couldn't have + past participle". This is the form that you will mostly come across in reading and conversation, I would say. Actually, that is what I say.
"This is the form that you will mostly come across in reading and conversation, I would say. Actually, that is what I say. "
What difference in meaning does it make if i say:
I would say.
I will say.