1
general::
You are aware, you see, do you remember, as in She's very lonely, you know, so do go and visit, or You know, this exhibit ends tomorrow, or You know that black dog our neighbors had? She was run over a year ago. This phrase is Also quite often a conversational filler, equivalent to "um" and occasionally repeated over and over (as in It's a fine day for, you know, the beach, and, you know, we could leave now); this usage is more oral than written, and many consider it deplorable. [Late 1500s]
American Heritage Idioms
2
general::
Phrase(s): you know
an expression placed on the end of a statement for pause or emphasis. (This expression is often overused, in which case it is totally meaningless and irritating.) • Tom: Sure, I spent a fortune on this car. Can’t take it with you, you know. Rachel: But there are better things to do with it here and now. • Bill: Do you always lock your door? Tom: Usually. There’s a lot of theft around here, you know.
McGrawhill's American Idioms And Phrasal Verbs