Let's look at the following sentence. "You know, they say you shouldn't eat too much sugar." Should there be a semi-colon after "know"? I'm almost positive that "You know" and "they say" are both independent clauses, but I've never seen sentences like that written with a semi-colon. I always see "You know, they say [insert saying]." Or, would "they say" be the direct object, and there shouldn't be either punctuation mark?
I believe that in that sentence there shouldn't be a comma after know, but it's in there to emulate how people speak. If i'm right about that (which I could be totally wrong) then "they say" would be the object of the verb "know". I can't how a semicolon would work there, it isn't a comma splice because "you know" is referring directly to what comes next. I hope that helps Warp, and If i'm wrong, I hope someone will tell me!
Why do you think they are independent clauses? As far as I can see "you know" is an insert and the entirety of "they say you shouldn't eat too much sugar" is an independent clause that contains an embedded dependent clause ("you shouldn't eat too much sugar"). Neither "you know" nor "they say" as used there could stand on its own.
I thought "You" and "they" would be the subject, and "know" and "say" would be the predicate. Also, how is "you shouldn't eat too much sugar" a dependent clause?
"You know" could be used as an independent clause, but I reckon it isn't in that case. Without an object to the clause it is just an abstract thing you do: You live, you think, you know. And of course, if "knows" is used in its usual transitive way then it's not an independent clause because it has "they say you shouldn't eat too much sugar" as its object and so part of the same clause. But "you know" is a textbook example of an insert (and the textbook in question is the Longman Student Grammar of Spoken and Written English). It's invariant (you wouldn't say "He knows, ..." or "they know..." in the sense you are using it there) and it can be moved around the sentence without changing the meaning. As an insert it doesn't parse into individual components, it's an idiom that has to be treated as a single unit. Yes, sorry, "you shouldn't eat too much sugar" is independent, not dependent. My point is, though, it is embedded; that is, it forms part of the larger clause. "They say" needs an object (unless you are using it in a rare abstract sense), and what is it's object? It's whatever is said -- which can be almost much linguistic construction whatsoever, up to and including a whole sentence. It doesn't matter what it would be if it were on its own; in this sentence it is not on its own. It is simply serving as the object of "They say x". So the clause structure is "You know, [they say [you shouldn't eat too much sugar]]", not "[You know], [they say] [you shouldn't eat too much sugar]".
