Erm now, something that puzzled me for quite a long time when I started out doing philosophy of language er one or two years ago erm  frequently you hear claims or we hear claims to the effect that this is a logical form of this sentence or this is the structure of this sentence, or this is the semantic structure of this sentence and I was never quite sure what that actually meant erm it's partly because  apart from Davidson, erm a lot of people who write on these issues don't actually tell you what the background theory is and exactly what the point of the assignment of structured sentences is supposed to be, erm however after thinking about it for a while, I've arrived at the following  following general view  there are at least three rather different enterprises er which might lead you to assign sentence structure and er one needs to figure out the relations between them.