Student or Learner
It is not necessary to postulate that the expression  presupposes some unspoken preamble such as [5a] but, rather, such as [5b]:
the mud on your coat 
There's some mud on your coat. [5a]
You know there's mud on your coat. [5b]
(A Comprehensive Grammar of the English Language; pg 269)
Would you be so kind to explain to me what the original sentence suggests or slightly paraphrase it?
(Not a Teacher)
I guess what the author is trying get at is whether or not the phrase 'the mud on your coat' assumes that 'You know there's mud on your coat.'
Here's my paraphrase:
The phrase 'the mud on your coat' all ready assumes [5a]. The real question is does it presume [5b]?
Last edited by SlickVic9000; 27-Mar-2012 at 20:05.